nrao june 27-30, 2004
DESCRIPTION
NRAO June 27-30, 2004. SARA 2004 CONFERENCE. Plasma Bubble Detection & Analysis at 20 MHz. Professor John C. Mannone Professor Wanda Diaz Central Piedmont Community College University of Puerto Rico Duke-Cogema-Stone & Webster Department of Physics - PowerPoint PPT PresentationTRANSCRIPT
NRAO June 27-30, 2004
PlasmaBubble
Detection&
Analysisat
20 MHz
Professor John C. Mannone Professor Wanda DiazCentral Piedmont Community College University of Puerto RicoDuke-Cogema-Stone & Webster Department of Physics Charlotte, NC San Juan, Puerto Rico
Spectral Analysis Techniques Developed
SARA Conference July 2003Solar Physics with 20 MHz AntennasFocus on Solar FlaresUnderstanding Solar Radio Propagation EncountersFrequency Analysis Computer Simulation
Website Creation Sept 2003NASA/Radio Jove Bulletin Article October 2003ORION Lecture October 2003
Solar-Ionosphere ConnectionSimultaneous Comparative Solar Burst AnalysisDevelopment of Radio Scintillation Experiments
SARA Conference June 2004 Plasma Bubble Detection & Analysis
"DETECTION AND ANALYSIS OF PLASMA BUBBLES AT 20 MHz RADIO FREQUENCY"
ABSTRACTCharge deficient holes in the F-region, called plasma bubbles, are typically detected above the equatorial zone. Some of the traditional techniques of detection involve sensitive receivers called riometers tuned to 30 MHz to record time variations or rocket-borne Langmuir probes measure the fluctuation of electron number density. In this work, the electron number density variations are recorded indirectly. Astrophysical radio waves are modulated by these variations as they travel through the ionosphere. Spectral analysis of decametric radio signals acquired with 20 MHz antennas will provide similar information about the ionosphere. The behavior of the radio noise floor will show if radio light is scintillated. This technique is applied to data from Puerto Rico. Though just north of the magnetic equatorial zone, power spectra disclose radio twinkling by the sudden post-sunset onset of plasma bubbles just before local midnight.
Irregularities and Radio Scintillation
Optical Twinkle- Variation refractive index caused by fluctuations in mass density in the turbulent atmosphere (troposphere)
Radio Twinkle- caused by random fluctuations in electron number density in the ionosphere
Important inNavigation CommunicationPulsar Research
Science & Industry Radio Scintillation Detection
30 MHz Riometer- very sensitive low noise receiver and 4-element Yagi arrays
Radar Backscatter
Satellite Transmission- FLEETSAT (254 MHz), GPS Satellites (~1.2 - 1.6 MHz)
Rockets Instrumented with Langmuir Probes- ne fluctuations
Global UV Imager maps ionospheric ions fluctuations (volume emission rate in the far UV at 135.6 nm, due to the radiative recombination of the F-layer predominant ion O+, is proportional to ne
2)
Our Methodology on Radio Scintillation Detection
The extent of amplitude modulation of 20 MHz galactic radio background noise by the medium in its path (not necessarily restricted to the ionosphere) is determined and compared with known characteristics.
The signal is too noisy to see the scintillations directly with the simple inexpensive receiver and phased array dipoles used; however, spectral analysis reveals the behavior of the noise floor.
In concert with additional information, such as the time and location of the disturbance, geomagnetic activity, space weather, etc., the spectral analysis is a good tool that will help determine or corroborate the state of the ionosphere.
The Ionosphere is a Plasma
Hot Plasma
Electric and Magnetic Fields Govern the Solar Plasma
Radio Emission Mechanisms
ContinuousThermal (Coulomb Scattering)Non-thermal (Synchrotron Radiation)
DiscreteAtom Transitions (High Rydberg States)Hyperfine Transition ( 21 cm spin-flip)Molecular Transitions (methanol lines; water masers)
Radio Spectraof Various Sources
Adapted from Fig. 6.2 Atmospheric Window and Sky Brightness (NRAO library)
Frequency, MHz20
p = -0.65
Anatomy of the Ionosphere
Layout, Composition, FormationDynamics of Fields and Sources (g, E, B, v, P, m, n, j)Connectivity/Nonlinear DynamicsBoundary Flows/ShocksSpace Weather/Terrestrial Weather (El Nina South Atlantic Oscillation, Hurricanes)Diurnal, Seasonal, Solar Cycle Effects
Exosphere (space weather)Exosphere (space weather) 40,000 miles / 64,400km40,000 miles / 64,400km(contains Plasmasphere & Magnetosphere)(contains Plasmasphere & Magnetosphere)
MesosphereMesosphere 50 miles / 80km50 miles / 80km
ThermosphereThermosphere400 miles /640km400 miles /640km
(Ionosphere straddle these two spheres)(Ionosphere straddle these two spheres)
StratosphereStratosphere~30 miles / 50km~30 miles / 50km
Troposphere (neutral atmosphere/weather)Troposphere (neutral atmosphere/weather)
5 miles / 8.1km at poles5 miles / 8.1km at poles
10 miles / 16.1km at equator10 miles / 16.1km at equator
Solar Wind Deforms Earths Dipolar Magnetic Field
A constant stream of particles flowing 106 mph from the Sun’s corona extends beyond Pluto’s orbit.
Note: green line is for Martian ionosphereChapman profile 120 km, max ne = 5x104 cm-3
Ionospheric Plasma
Formed from complex collision dynamics and photo-ionization of air molecules involving cosmic rays and UV light.
(106 cm3 = 1 m3 )
Transparency of Earth’s Atmosphere
O2 and N2 absorb all < 290 nm H2O and CO2 block 10 to 1 cm
Universe, 5th ed. Kaufmann and Friedman
Electron Plasma Frequency- Radio Wave Passage
Or the Langmuir Frequency of Plasma Oscillation
pe = (4e2n0/me)1/2
~15 MHzon the day side of the earth near sunspot maximum and ~10 MHzon the night side near sunspot minimum
Layer opaque to all lower frequencies
Significant Ionospheric Scintillationof Radio Waves
Caused by Plasma Instabilities
Polar/Auroral Zone Particle Precipitation
Equatorial ZonePlasma Plumes and Bubbles
Mid LatitudesStorm Enhanced Density (SED) from high latitudesSudden Storm Enhancement (SSE) from low latitudes
Plasma Plumes and Bubbles
Equatorial ionosphere illustrationCoupled Ionosphere-thermosphere forecast model
Linked to theoretical growth-rate model (left)Linked to non-linear plasma bubble evolution (right)
Rayleigh-Taylor Instability&
E x B Drift
RADIO JOVE SYSTEM
Improved version over Radio Jove RJ1.1 receiver, the RF-2001A is used here (also designed by RF Associates, Dick Flagg)
Local oscillator generates a waveform at frequency around 20.1 MHz. The range of frequencies to tune at 19.950-20.250. The JFET transistor amplify incoming signals by a factor of 10. The receiver input circuitry is designed for a 50 Ohm antenna.
The double dipole antenna ( Radio JOVE) is 10 feet above the ground, aligned east-west, in-phase so the beam is directly overhead. The maximum gain for a horizontal dipole is 7.3 dBi. Beam width is 115 degrees. The VSWR is below 1.5:1
Receiver noise figure < 5dB ( 620K). At the operating frequency of 20.1 MHz the galactic background temperature on the order of 50,000 degrees (this is consistent with the plasma temperature vs. ne chart).
Can Equatorial Plasma Bubbles be Detected?
Phenomena normally in the equatorial zone+/- 20 degrees from the magnetic equator
Most southern participating site is Puerto Rico withGeographic latitude 18.3N, but Geomagnetic latitude 28.2 N
Data was collected hourly for a period before sunset to after sunrise (6 AM to 6 PM Atlantic Standard Time). Arbitrarily, the antenna signal was sampled for the first 10 minutes of each hour. The sampling rate was 1 Hz.
Though the bubbles only survive around 30 minutes, the antenna is seeing numerous irregularities. (Future experiments will acquire more data over a shorter time interval and at a higher sampling rate).
Plasma irregularity
Radio wave path
Latitude of zenith pointAntenna site
Greatly exaggerated for clarity
3 dB
is angle between the vertical and the half power antenna beam width
is the maximum latitude displacementTo see an irregularity at height z (typically 600 km)
R is the radius of Earth: 6378 km
z
R
Simple trigonometry =>
sin()/sin() = R/(R + z)
Dipole patternfree space vs. close to the ground
Questionably in the Zone:need 8 degrees (28-8 = 20), may only have 3 degrees latitude
E-W phased dipole array with a 60 degree full beam widthand disturbance at 600 or 1100 km, allows no more than 2.8 or 4.8 degrees latitude difference, respectively. (E-W anti-phasearrangement is preferred allowing 13-19.5 degree reprieve)
This configuration falls short. However, a free dipole array was assumed.
With the antenna 10 ft (3 m) above the ground (1/5-wavelength), the antenna pattern may become distorted. Though less sensitive, it may now see into the equatorial zone similarly to the anti-phase capability.
Preliminary Data Reduction Sequence
-Radio Skypipe Pro software SPD files converted to TXT files
-Save data in Word document which automatically delimits the data into 3 columns: date, time, signal strength
-Correct logging errors (37:.94 must be changed to 37:0.94;often jumps at the minute intervals; other errors in format or placement)
-Copy data into Excel and format illegible data
Data Collection & Preparation
-Note that Excel truncates the Hour in Column B. Therefore, label column as time, min:sec after the hour (e.g., after 22Z). However, computations in Excel will treat this a fractional day.
-Compute sampling interval time (in seconds) in cell D4 type (=(B4-B3)*24*3600)
-Plot Signal Strength vs. Time to reproduce the time series.
-Compute sampling statistics
-Load FFT capability in Excel by executing the submenu pathTools/Add-Ins/check Analysis Toolpak/OK
-Excel algorithms require exactly 2N data points for FFT, Use 512. 1024, etc not to exceed 4096.. Truncate or pad as necessary.
Sampling Statistics
-Perform FFT (Tools/Data Analysis/Fourier Analysis/OK):Input the range of data for the signal strength matching 2N points; e.g., C4:C515; direct output, e.g., F4:F515
-Decimate the frequency according to N. That is, step-wise increase the frequency (sampling frequency/N).
-Calculate spectral power: square the magnitude of the complex number returned by the FFT (=IMABS(F4)2); propagate to N/2 -1 points to avoid reflection of results.
-Plot Power Spectrum: Power vs. Frequency.
-Scale the plot down by a factor of around 104 to105 to see the spectral components above the noise.
-Plot Log Power vs. Log Frequency with close attention to the 100 to 1000 millihertz range for behavior of the noise floor.
Spectral Analysis
Left Portion of Excel Spreadsheet Analysis
date time min:sec after 03Z signal strength sample interval, sec FFT 512 points frequency, mHz Power log f log Power6/7/04 00:01.5 1193.28717 782314.445885544 0 6.12016E+116/7/04 00:02.5 1194.124165 1.015 -39544.0593033628+106537.25203505i 1.933628666 12913918697 0.286373 10.111066/7/04 00:03.5 1160.717424 1 29831.53725076+26017.567578558i 3.867257333 1566834437 0.587403 9.1950236/7/04 00:04.5 1101.4359 1.015 -17477.0974059173+9575.94727672195i 5.800918549 397147700 0.763497 8.5989526/7/04 00:05.6 1098.102841 1.016 4983.27856232657+29844.0384449754i 7.734579765 915499695.9 0.888437 8.9616586/7/04 00:06.6 1061.301716 1 4626.20334632665+787.248194263408i 9.668240981 22021517.12 0.985347 7.3428476/7/04 00:07.6 1025.577841 1.016 -9001.43903929736+15509.3409370569i 11.6019022 321565561.1 1.064529 8.507276/7/04 00:08.6 1082.086039 1 8976.53676117491+10632.3539019751i 13.53556341 193625161.7 1.131476 8.2869626/7/04 00:09.6 1092.537121 1.015 -5320.0314961863+1362.10908300627i 15.46922463 30158076.27 1.189469 7.4794046/7/04 00:10.6 1061.860795 1 -92.2711573202675+14072.1393592358i 17.40288585 198033620.1 1.240621 8.296739
Spreadsheet Calculations
Right Portion of Excel Spreadsheet Analysis
date time min:sec after 03Z signal strength sample interval, sec FFT 512 points frequency, mHz Power log f log Power6/7/04 00:01.5 1193.28717 782314.445885544 0 6.12016E+116/7/04 00:02.5 1194.124165 1.015 -39544.0593033628+106537.25203505i 1.933628666 12913918697 0.286373 10.111066/7/04 00:03.5 1160.717424 1 29831.53725076+26017.567578558i 3.867257333 1566834437 0.587403 9.1950236/7/04 00:04.5 1101.4359 1.015 -17477.0974059173+9575.94727672195i 5.800918549 397147700 0.763497 8.5989526/7/04 00:05.6 1098.102841 1.016 4983.27856232657+29844.0384449754i 7.734579765 915499695.9 0.888437 8.9616586/7/04 00:06.6 1061.301716 1 4626.20334632665+787.248194263408i 9.668240981 22021517.12 0.985347 7.3428476/7/04 00:07.6 1025.577841 1.016 -9001.43903929736+15509.3409370569i 11.6019022 321565561.1 1.064529 8.507276/7/04 00:08.6 1082.086039 1 8976.53676117491+10632.3539019751i 13.53556341 193625161.7 1.131476 8.2869626/7/04 00:09.6 1092.537121 1.015 -5320.0314961863+1362.10908300627i 15.46922463 30158076.27 1.189469 7.4794046/7/04 00:10.6 1061.860795 1 -92.2711573202675+14072.1393592358i 17.40288585 198033620.1 1.240621 8.296739
Spreadsheet Calculations
The frequency is stepped in about 2 mHz increments (step = sampling frequency/N = 990 mHz/512 samples)
UPR 6/7/04 03Z
0
500
1000
1500
2000
2500
3000
3500
58:33.6 01:26.4 04:19.2 07:12.0 10:04.8 12:57.6
time min:sec after 03Z
sig
na
l str
en
gth
Signal Strength vs. Time Graph Reconstruction in Excel10 minute time series sampled at 1 Hz (990 +/- 7 mHz)
Apparently uneventfulradio noise, just a dc off-set
20 MHz Radio Background NoiseUniversity of Puerto Rico, June 6, 2004 11 PM local time
Power Spectrum, UPR June 7, 2004 03Z (scaled 10^4)
0.00E+002.00E+074.00E+076.00E+078.00E+071.00E+08
0 200 400 600
f, mHz
Po
we
r
Typical Power Spectral Density (Power vs. Frequency)not very revealing except for ringing
Diffraction and Scattering Models p1
Scintillation caused by change in refractive index, n, caused by diffraction on irregularities related to electron number density fluctuations or atmospheric turbulence.(Appleton-Hartree equation)
Irregularity size >> wavelength, wave front is disturbed, get random phase modulation; further modulation occurs before it reaches the antenna => complicated diffraction pattern.
Temporal variation if source is moving relative to the receiver.
Diffraction and Scattering Models p2
Phase screen, simplest model: irregular layer replace by equivalent thin screen a distance z to the antenna (multiple screen are necessary for extended medium and an inhomogeneous background).
Fresnel Diffraction leads to power law frequency dependence f-p where p is the spectral index.
Various types of scintillation lead to different spectral indices: the quiet sky 0.65, typical ionospheric scintillation 8/3 (2.5), plasma bubbles range 2-8 with average 4, tropospheric scintillation 11/3, interstellar scintillation like ionospheric without the seasonal or geographic restrictions.
Spectral Analysis
Fresnel Zone Speed of rising plasma bubble is estimated from the corner frequency fc: (V = (z)1/2 fc)
Spectral Index, p obtained from log Power vs. log frequency plot after the roll-off (around 50 millihertz) to about 1 Hz or perhaps 2 or 3 for very strong scintillation (cut-off frequency for Fresnel filtering). Therefore, spectral behavior is examined from about 100-1000 millihertz.
S4, Scintillation Index (normalized time averaged signal strength) (not a good index for our experiment since our receiver is not sensitive like a riometer).
Ionospheric Plasma by VHF Waves, R.P. Patel, et alPramana Journal of Physics, India Academy of Sciences, Vol 55, No. 5 & 6, Nov/Dec 2000, pp. 699-705
Spectral index p = 4 for plasma bubblesover Varanasi, India
Spectral index p = 5 for plasma bubblesover San Juan, Puerto Rico
02Z
33.5
44.5
55.5
66.5
77.5
0 1 2 3
log f
log
po
we
r02Z
y = -1.1241x + 8.0911
33.5
44.5
55.5
66.5
77.5
2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8
log f
log
po
we
r
04Z
33.5
44.5
55.5
66.5
77.5
0 1 2 3
log f(mHz)
log
Po
wer
04Z
y = -0.7906x + 7.5143
33.5
44.5
55.5
66.5
77.5
2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8
log f(mHz)
log
Po
wer
Before and After the Irregularity log power vs. log frequency
Time, hrs 6/7/04 Spectral Index (100-1000 mHz)-2 -0.6472-1 -0.16450 -0.43391 0.29372 -1.12413 -5.03004 -0.79065 -1.20006 -0.49727 -1.31398 -1.44409 -0.2128
10 -1.3572
Time Variation of Spectral Index
June 6, 2004 6 PM
June 7, 2004 8 PM 9 PM
11 PM
6 AM
June 6, 2004 sunset 6:57 PM 23Z = -01Z 6/7/04June 7, 2004 sunrise 5:48 AM = +10Z 6/7/04
03Z
3456789
10
0 1 2 3
log f (millihertz)
log
po
we
r
Corner frequency 316 mHz relates to the first Fresnel zoneSize and speed of irregularity can be estimated from this
Significant change in slope suggests multiple phenomena
50 100 1000 mHz
A major change is indicated in the condition of the ionized layerduring the measurement interval.
Each linear segment is analyzed between 100 and 1000 mHz,the correct range for scintillation observations (the “trend line” feature in Excel is used to obtain an unbiased linear regression)
03Z
y = -0.8337x + 8.635
44.5
55.5
66.5
77.5
2 2.1 2.2 2.3 2.4 2.5
log f
log
po
we
r03Z
y = -5.0327x + 19.105
44.5
55.5
66.5
77.5
2.5 2.6 2.7 2.8 2.9 3
log f
log
po
we
r
Change in Spectral Index
Radio Noise at 20 MHz6 PM and 6AM Local Time Puerto Rico
-6
-5
-4
-3
-2
-1
0
1
-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
UTC Time, hours June 7, 2004
Sp
ectr
al I
nd
ex10
0-50
0 m
illi
her
tz
Radio sky backgroundspectral index -0.65
Post-sunset (-01Z) and Pre-midnight (+04Z) Growthof Suspected Plasma Bubble
Diurnal Variation of Plasma Bubble Growth
View of Eastern Sky/Milky Way from Puerto Rico June 6, 2004 11 PM
Geomagnetic Activity May Enhance the Occurrence of Irregularitiesin the Mid-latitude Region
Geomagnetic coordinate treated in this page is "geomagnetic dipole coordinate" referring to the geocentric dipole field approximating the geomagnetic field based on International Geomagnetic Reference Field (IGRF). The poles are the intersections of the dipole axis with the Earth's surface at (79.5N, 71.6W) and (79.5S, 108.4E)(IGRF 2000), and move slowly according to "secular variation of the geomagnetic field".
Geomagnetic latitude and longitude are defined as shown in the illustration.
HAARP Flux Magnetometer
Geomagnetic storminess is usually indicated in oscillatory variations in the earth's magnetic field. Additional detail concerning the nature and severity of the ionospheric disturbance can be found through analysis of the three components of the field.
"H" component positive magnetic northward
"D" component positive eastward
"Z" component positive downward
The Geomagnetic Disturbance Storm IndexDst (nT)
During a typical geomagnetic storm the magnetic field is depressed (H component is negative) everywhere in the middle and lower latitudes of the Earth.
From Some of my Radio Astronomy Web Resources“Adventures in Astronomy by John C. Mannone”
Society for Amateur Radio Astronomers (SARA) NASA Project Radio Jove Space Physics & Aeronomy on the WebSolar X-ray & Geomagnetic Storm MonitorSun-Earth Connection Data Availability Catalog Mission Overview MatrixWIND Daily Spectrogram Plots and Type II & IV Solar Burst Lists SOHO Data The Sun NowSOHO InstrumentsSolar & Heliospheric Weather Model (IMSAL) Solar Physics on the WebLatest Solar EventsYohkoh GOES Data Base Browser Australian Space Weather Agency
AsideStorm Enhanced Density
SED is the ionospheric signature of the erosion of the outer plasmasphere by ring current-induced disturbance electric fields. The low-altitude ionosphere: appearance of sunward-convecting regions of enhanced plasma density at mid latitudes.
Millstone Hill incoherent scatter radar has observed SEDs in the pre-midnight sub-auroral ionosphere during the early stages of magnetic storms.
These high-TEC plumes of ionization appear at the equatorward edge of the mid-latitude ionospheric trough and stream sunward driven by poleward-directed electric fields at the equatorward limit of region of sunward convection.
SED
High TEC observed northern Florida ( July 15, 2000 Kp=9 event) and the north-central USA is more typical of pre-midnight SED events for Kp=5 or 6.
Snapshot of SED plume in the post-noon sector obtained vertical TEC from > 120 GPS receiving sites during a 15-min interval. Red contour denotes the instantaneous position of the SED/TEC enhancement.
CONCLUSIONS
-spectral analysis of radio signals provides a potential probe of the intervening media the wave propagates through
-inexpensive and extensive equipment and readily available resources renders this favorable to amateur radio astronomy
-state of ionosphere can be examined by monitoring the radio noise floor as a function of time in concert with space weather and geomagnetic parameters
-major irregularities like SEDs and plasma bubbles can be detected in midlatitudes
-June 7 decametric data clearly shows the evolution of an irregularity that fits the characteristics of a plasma bubble over Puerto Rico. Geomagnetic conditions were not remarkable.
Radio Poetryby
John C. Mannone
Plasma Bubbles
The furious light sinks belowAnd air above is tempered so
And not just anywhere this airBut somewhere in equator’s care
The daytime heated air is trappedWhile colder air on top is zapped
Which tampered atoms’ state of rest And left as ions their new guest
Hapless misty heavy layerGrows a wave of Rayleigh-Taylor
At first a ripple, then a waveWhich drive unstable air to crave
The upper reaches-- freedom boundThe bubbles soar to higher ground
Peculiar pockets rising fastThe air had seen a solar blast
Holes large left with charge in troubleRising high as plasma bubbles
Gently urged by E cross BThese fickle fields that they do see
Not seen with ocular boreBut quivers in the radio floor
Bubbled pockets confuse the rayFrantically bend it everyway
And when still dark and very lateThe plasma plumes do dissipate
No longer there in hassling poiseThe radio whispers quite noise.
By John C. MannoneApril 30, 2004
Credits
University of Puerto RicoWanda Diaz
Tamke-Allan ObservatoryDavid Fields
NASA/Radio Jove ProjectJim Thieman, Chuck Higgins, Leonard Garcia
And many others, but especially…
… My Lord, Jesus the Christ
APPENDIXMISCELLANEOUS
ARTICLES, RESOURCES, AND EXPANDED DETAILS
A Few FFT Basics
The Fourier Transform, FT is an analog tool used to analyze the frequency content of continuous signals.
The Discrete Fourier Transform, DFT is a digital tool used to analyze the frequency content of discrete signals.
The Fast Fourier Transform, FFT is an algorithm to rapidly compute the DFT.
N = total number of discrete samplesT = total sampling time; don’t confuse with periodt = time increment between samples = T/N fs = the sampling frequency = 1/t
N is often restricted to powers of 2
F( f ) f (t)e i2ftdt
F(kf ) f (nt)e i2kf nt
n0
N 1
Digitizing the analog signal must be frequent to faithfully reproduce it.
Nyquist criterion fsampling > 2fmaximum (Image processing considerations of brightness and contrast suggest a factor of 2.57).
Aliasing (fold-over or mixing) occurs if Nyquist sampling is violated.
ALIASING EXAMPLES
(1) Analog electronics: heterodyning is used for tuning; anti-aliasing filters (low pass) filter unwanted signals before the A/D conversion.
(2) Engine timing: slow sampling by a strobe light can arrest the motion of a rotating engine.
(3) Movie making: frames per second may be too slow and “wagon wheels” will appear to stop or rotate backwards.
(4) Moiré patterns: slight motion of one of two overlapping (semitransparent) repetitive patterns creates large scale changes in patterns.
Fourier Transform Examples
Also Gaussian pulse transforms to a Gaussian frequency
Random noise can be modeled as a series of spikes (think of a train of very narrow Gaussians); transforms to huge Gaussian peak due to additive effect and a noisy tail)
Spectral Features Revealed
Power vs. Frequency Plot
Dynamic nature of the ionosphere as well as the history of travel through multiple media affecting the radio wave leads to combs, bands, modulation envelopes. Visualize Moiré patterns from multiple screen models.
Excited cavity modes and other ringing lead to resonant lines: fundamental vibration and its harmonics.
Nonlinear interaction between boundaries may lead to subharmonics.
Radio Jove Archive
Comparative
Solar Burst Data
SC, MI, NM, MT, HI
March 26, 2002 22:23 Z
Time & Frequency Analyzed in Excel
Radio Noise Floor
log Power vs. log Frequency Plot
The spectral features are superimposed on a radio sky background.
The behavior of this floor is an indicator of the state of the media the radio wave propagates through.
Log-log plots reveal spectral index.
HIGH FREQUENCY ACTIVE AURORAL RESEARCH PROGRAM
2 x 2 array of 5-element yagi antennas &
very sensitive low noise receiver
HAARP 30 MHz VHF RIOMETER
Flares and Prominences
Solar flares are tremendous explosions on the surface of the Sun. A billion megatons of TNT energy release across the entire electromagnetic spectrum in just a few minutes.
Coronal Mass EjectionsTH
Disruption of flow of the solar wind, compresses magnetopause magnetic fields
dB/dt => strong currents induced on power grid
Coronal mass ejections are often associated with solar flares and prominence eruptions but they can also occur in the absence of either of these processes.
NOAA SPACE ENVIRONMENT CENTER
Space Weather Forecasting
Measurement and Modeling Requirements
Living with a Star Measurements WorkshopNASA Goddard Space Center
February 9-10, 2000
Gary Heckman
NOAA Space Environment Center
NOAA SPACE ENVIRONMENT CENTER
SEC Users
Aviation Aerospace industry Biological systems Education Geophysical/seismological applications Navigation News media Pipeline companies Power interests Radio operations Satellite communications Satellite environment Telephone communications Man in space Scientific experiment conditions Vendors
Geomagnetic field
Ionosphere
Energetic particle environment
Atmospheric density
Space Weather Domain
NOAA SPACE ENVIRONMENT CENTER
NOAA SPACE ENVIRONMENT CENTER
Products
Forecasts (text and models) (1-3 days,
month, years)
Alerts (right now)
WWaarrnniinnggss ((uupp ttoo oonnee hhoouurr))
WWaattcchheess ((uupp ttoo oonnee hhoouurr))
Advisories
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Measurements and indices (right now to a
few hours)
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Ionosphere
Geomagnetic field
Neutral Atmosphere
Energetic Particles
Interplanetary
Models
Interplanetary disturbance initiation
Interplanetary observations
In-situ observations and models within each domain
Interplanetary/magnetosphere interaction models
Solar EUV and X-ray Flux Energetic particles
Solar activity evolution--observations and models
Sun
Earth
Observing and ModelingRequirements
NOAA SPACE ENVIRONMENT CENTER
Verification is a critical function
NOAA SPACE ENVIRONMENT CENTER
Solar Measurement Priorities
• CME initiation in 3 dimensions to drive interplanetary modelsDirectionRadial velocityStructure and configuration
• Coronal Holes—observation and prediction of Earth impact
• EUV/X-ray flux—observation and prediction
• Evidence of energetic particle acceleration and interplanetary injection
• X-ray flares and radio bursts—observation and forecasting
• Evolution of active structures--prediction
• Cycle evolution--prediction
NOAA SPACE ENVIRONMENT CENTER
Space Weather Operational Models
2000 2005 2010 2015 2020 2025
Polar Cap Absorption Forecast
Auroral Clutter Specif ication
Auroral Emission Specification
Solar Wind Forecast
Data Assimilation Model
Polar Scintillation Forecast
Solar Flare Forecast
CME Propagation Forecast
Solar Energectic Particle Forecast
Radiation Belt Forecast
Equatorial Scintillation Forecast
Coronal Mass Ejection (CME) Forecast
Magnetospheric Particle Forecast
Magnetospheric Field Forecast
Ionosphere Forecast
Neutral Environment Forecast
YearNo model or only empirical models w hose accuracy does not meet user requirements
Model in use includes some physical understanding but does not meet most user requirements
Evolved capability but model still does not meet some critical requirements
Fully Capable Model
NOAA SPACE ENVIRONMENT CENTER
1999 2004 2009
Equatorial Scintillation
Polar-Orbit Sun Synchronous
Solar X-ray/EUV sensors
Solar X-ray/EUV Imager
Solar Coronagraph
Solar Wind on Sun-Earth line
Particles and Fields (LEO to GEO to HEO)
Auroral Imager
Stereo Solar Observer
GPS Occultation
Scintillation--Polar and Low Lat
TEC Networks
Ionosonde Sounders
Magnetometer Networks
All Sky Cameras
Solar Optical/Radio
Riometer Chain
Ground-based radars
Satellite Drag Observation
NPOESS
STEREO Japan L5 STEREO VIEWER
FSL Net
Ops EIT
IMAGE
SCINDA
DSP CEASE
GPS/OCCULTER
Ops IMAGE
Ops SCINDA
INTERMAGNET UPGRADES
ISOON/SRBL/SRS
Ops TEC NET
DMSP/POES
USGS/INTERMAGNET
SOON/RSTN
Thule
GOES
IONOSONDES
YOHKOH
ALL SKY Ops SYSTEM
EIT SXI
ACE
Ops Riometer
Ops CORONAGRAPH
JPL Net
C/NOFS C/NOFS Ops
GOES XRS GOES EUVHard X-ray spectrometer
SMEILASCO
COSMIC
SuperDARN Radars
DRAG Observer
R and D Less than fully capable operational systemFully Capable Operational SystemOperational, funded, or planned
Observing Gap
Planned but doubt about deploymentEarly stages of definition or distance into future lessens confidence of deployment, or no funding
NOAA SPACE ENVIRONMENT CENTER
2000
2005
2010
2015
2020
2025
YEAR
R and D Less than fully capable operational system Fully Capable Operational System Observing Gap
Space Weather Operational Sensors Timeline
Equatorial Scintillation
Polar-Orbit Sun Synchronous
Solar X-ray/EUV Imager
Solar Coronagraph
Solar Wind on Sun-Earth line
Particle Detectors (LEO to GEO to
HEO)
Auroral Imager
Stereo Solar Observer
GPS Occultation
Scintillation--Polar and Low Lat
TEC Networks
Ionosonde Sounders
Magnetometer Networks
All Sky Cameras
Solar Optical/Radio
Riometer Chain
Satellite Drag Observation
NPOESS
COSMIC
STEREO Japan L5 STEREO VIEWER
JPL Net
C/NOFS
Ops EIT
IMAGE
Solar Wind SENTRY
SCINDA
DSP CEASE
GPS/OCCULT
Ops IMAGE
Ops SCINDA
INTERMAGNET UPGRADES
ISOON/SRBL/SRS
DRAG Observer
Magnetospheric Constellation
Ops TEC NET
DMSP/POES
USGS
SOON/RSTN
Thule
GOES
IONOSONDES
YOHKOH
ALL SKY Ops SYSTEM
C/NOFS Ops
EIT SXI
ACE
OPS Riometer
LASCO Ops CORONAGRAPHSolar Polar Imager
GOES n/q
NOAA current, planned, or potential sensor or satellite set of sensors (e.g. GOES = GOES SEM)
Solar Wind Monitor
Note: this version of the plan has not incorporated sensors from the NASA-interagency initiative Living with a Star
NOAA SPACE ENVIRONMENT CENTER
New Operational Measurement Priorities
Provide quantities that meet user priorities
Information to fill weak links in Sun-Earth
propagation
Model drivers
Information that provides most reliable
forecasts or model input has higher rank
NOAA SPACE ENVIRONMENT CENTER
NOAA SPACE ENVIRONMENT CENTER
NOAA SPACE ENVIRONMENT CENTER
NOAA SPACE ENVIRONMENT CENTER
NOAA SPACE ENVIRONMENT CENTER
NOAA SPACE ENVIRONMENT CENTER
Radio Astronomy Web Resources
Society for Amateur Radio Astronomers (SARA) NASA Project Radio Jove Space Physics & Aeronomy on the Web
SOLAR DATA RESOURCES
(1) A compilation of useful SOHO and GEOS satellite data are found at "Solar Physics on the Web." Below is a solar storm and geomagnetic storm monitor from the site and a link to it which shows current x-ray and particle flux as well as other data like magnetometer readings. From
Solar X-ray & Geomagnetic Storm Monitor
(2) A comprehensive listing of NASA space-borne laboratories (ACE, Cluster, FAST, IMAGE, Polar, RHESSI, SAMPEX, SOHO, TIMED, TRACE, Ulysses, Voyager, and Wind) is extractable from the Sun-Earth Connection Data Availability Catalog Mission Overview Matrix. This is an extremely useful table and links to project descriptions and to live and archived data.
SECDAC Mission Overview Matrix
A useful item in the matrix is the link to various homepages and mission matrices for each of the above. These in turn have links to real-time data as well as to archived data. For example,
(3) Follow the links to the WIND spacecraft/WAVES instrument package/Waves homepage for electronic data products. Useful spectrograms of 20-14,000 KHz radio emissions are available from 1994 as well a a listing of Type II & IV solar burst events:
WIND Daily Spectrogram Plots and Type II & IV Solar Burst Lists
(4) Follow the links from the overview matrix to, say, SOHO/GONG/. It will show all the available SOHO data:
SOHO Data
Near Real Time Images and Movies, which features 3 of the 12 SOHO instruments:
EIT (Extreme UV Imaging Telescope) MDI (Michelson-Doppler Imager) Continuum and Magnetogram LASCO (Low Angle and Spectrometric Coronagraph Experiment)
(4a) The latest solar images with these instruments are found on
The Sun Now
(4b) From the SOHO Data page, choose the specific instruments under "Other Near Real Time Data," which represent other instruments aboard SOHO:
-VIRGO (Variability of Solar Irradiance and Gravity Oscillations) -Total Solar Irradiance -CELIAS (Charge, Element and Isotope Analysis System) -Proton and Energetic Particle Flare Activity Monitors, X-ray Flare Monitor -ERNE (Energetic and Relativistic Nuclei and Electron) Proton and Helium Intensity -MDI Far Side Imaging -SWAN ((Solar Wind Anisotropies) Far Side Imaging
For a description of the 12 SOHO Instruments, see the link below: SOHO Instruments
(4c) SOHO Data page also has the "Other Near Real Time Data" list, which has the particularly useful "Solar/Heliospheric Forecast" and "Recent Solar Activity" subheadings.
(5) Solar/Heliospheric Forecast has many good products including Solar wind model and Virtual Star Lab: Solar & Heliospheric Weather Model (IMSAL)
(6) From here, the Solar Data link is Solar Physics on the Web, which has comprehensive live and easy-to-use archive database (SOHO, GOES, WIND and the MEES Solar Observatory in Hawaii). Recommend to have some of these open when collecting Radio Jove data.
Solar Physics on the Web
(7) Recent Solar Activity: pinpoint the sunspot group that was active. Choose an event in the time span given, perhaps the strongest X-ray flare (in order of increasing intensity: A, B, C, M, X)
Solarsoft (Lockheed Martin Solar and Astrophysics Laboratory)
Header Information: Event Number, GOES Flare Classification, etc.
Flare sequence images (JavaScript frames w/ GOES flux plotted above)
TRACE event sequences 171A images (JavaScript, GIF Animations, or MPEGs), and Flare locator image Latest Solar Events
(8) Archived data (item 7) is harder to come by. Solarsoft is developing access to the database. However, the GOES data is easily retrievable back to 1991 from their Yohkoh solar x-ray telescope database: Yohkoh GOES Data Base Browser
(9) IPS Radio and Space Services provides several excellent resources under their "Space Weather" and "Solar" links. Real time Coolgura (18-1800 MHz) and Learmonth (25-180 MHz) Spectrograms as well as daily historical data up to 3 months (Coolgora). Space weather and ionospheric data is also provided.
Australian Space Weather Agency
COMPLEMENTARY RESOURCES
(1) A series of graduate level lectures on plasma physics: International Max Planck Research School on Physical Processes in the Solar System and Beyond at the Universities of Göttingen and Braunschweig.
Solar System School
(2) Ground based facilities, like the Alaskan High Frequency Active Auroral Research Program (HAARP). Ionospheric data (real time and archived) is available under the various instruments (Magnetometer, Riometer, HF Ionosound, Total Electron Content, Spectrum Monitor, etc.). See "Scientific Data from the Site" in the Table of Contents below,
HAARP Table of Contents
(3) Services, like those of Northwest Research Associates (NWRA) Space Weather and Ionospheric Scintillation Predictions. Very helpful staff. Site has good links to tutorials.
Space Weather Services Ionospheric Scintillation Predictions
(4) Products from several weather and lightning satellite databases.
Aviation Digital Data Service Vaisala Lightning Explorer
(5) Some climatological data to be displayed on a 3-dimensional globe that one can manipulate (a good option but may require a free software download). (to 1995): The GLOBE Program
Images provided by Weather Services International Corp. (WSI) and NASA though the Global Energy and Water Cycle Experiment Continental-Scale International Project. Currently Available 1 April 1995 to 18 April 1997, Daily 19 April 1997 to 29 May 2004, Hourly Select the Radar product in the link below: NEXRAD Archived Radar
(6) Specialized Databases like the 81.5 MHz Interplanetary Scintillation. Some animations are available for 1990-1993.
Interplanetary Scintillation (IPS) Data IPS Hammer-Aitoff Projection March 1992
(7) Prediction of Jupiter storms is based on the interaction of the Jovian moon, Io, with the Jovian magnetic field. Professor Kazumasa Imai (Kochi National College of Technology, Department of Electrical Engineering) has prepared a useful prediction tool. This will prove invaluable to assess the potential influence of certain Jovian storms occurring concurrently with a solar burst (this speculation will be defended later).
The Jovian Daily Ephemeris
(8) Solar and Jovian data files from October 1999 (mostly decametric) can be accessed via the link on the Radio Jove homepage (above). It can be directly accessed via "View Current Data Archive," which allows one to specify the fields to view (be sure to mark "Data Products").
Radio Jove Data Archive
(9) Other than to look at picture files of the signal traces in the archive, one will need the SPD wave files to manipulate the data. Radio Sky Publishing has free PC software that allows strip chart recording and sharing files over the internet. The affordable Pro version may be required for some features, like converting the SPD files to TEXT files which can be manipulated in EXCEL.
Radio Sky Publishing/SkyPipe Software
(10) Planetarium software
Starry Night Planetarium Software Cartes du Ciel (Sky Charts)SEDS Planetarium Software List
(11) Geographical Information is obtained from several databases when the planetarium software falls short:
USGS Geographic Names Information System Topographical Maps & Coordinates (Topozone) Maporama: Lat/Lon for Specific Location
(12) Astronomical information
Greenwich Sidereal Time Calculator (Astro Java)
(13) Geomagnetic Latitude and Longitude
Convert Geographic to Geomagnetic Coordinates
Recorded Radio Signal Differences Explained
ReceiversDesignElectronic NoiseCalibration
AntennasFrequencyAntenna PatternLocation
Local Obstructions Geographic Coordinates
Ground CapacitanceDistance Above GroundSoil Type
Calibration
Recorded Radio Signal Differences Explained
Transmission LinesImpedance MismatchMicrophonic Cable/Wind Loading
Man-made InterferencesPower LinesCycling Electrical Equipment (motors)Transmitters (Radio, TV, proposed digital phone lines…)
Recorded Radio Signal Differences Explained
Natural Interferences and PhenomenaAtmosphere
LightningWeather
IonosphereRadio Twinkling
MagnetopauseShocksSchumann Resonances (VLF Earth Cavity)
CoronaCoronal Loop OscillationsPlasma Instabilities
Photosphere/Flares/ProminencesBunching/Stretching Magnetic Field Lines
Solar CavityResonant “Acoustics”
Tropospheric Scintillation
-Scintillation
A rapid fluctuation in amplitude, phase and arrival angle
-Refractive Index
Small irregularities caused by temperature inversions
i.e., reverse of lapse rate due to:
trade wind inversion, frontal inversion,turbulent boundary
Tropospheric Scintillation
-Dry Scintillation: no fading
-Wet Scintillation: causes fading when raining
Absorption BandsAbsorption Bands
Elevation angle 90Elevation angle 90°°
Latitude 45°NLatitude 45°N
Water VapourWater Vapour
22.2, 182 and 325 GHz22.2, 182 and 325 GHz
OxygenOxygen
60 and 119 GHz60 and 119 GHz
Small losses < 10 GHzSmall losses < 10 GHz
The ionosphere, the closest naturally occurring plasma.
Signals transmitted to and from satellites for communication and navigation purposes must pass through the irregularities in the ionosphere (most common at equatorial latitudes, although they can occur anywhere)
Computer simulations of ionospheric processes (ionospheric model developed at the University of Alaska, Fairbanks.) The development of visualizations of this type have allowed us to see and appreciate the enormous variability and turbulence that occurs in the ionosphere during a major solar geomagnetic storm.
Adapted from “The Importance of Ionospheric Research”http://www.haarp.alaska.edu/haarp/ion2.html
VHF Satellite Scintillation
ANTENNA LOCATION
SLOPE OF FIRST SEGMENT
SLOPE OF SECOND SEGMENT
CORNER FREQUENCY mHz
IONOSPHERE
Receiver Noise
0 - - No bias
SC 0 -0.59 224 Normal Radio Sky
MI 0 -1.05 363 Off-normal
NM -1.25 0 227 Weak Scintillation
MT -2.48 0 413 Classic Scintillation
HI -4.67 -0.98 130 Strong Scintillation
March 26, 2002 Solar Burst Event 21:23Z
Excerpt prepared for NASA Radio Jove Bulletin; full details on my web site Adventures in Astronomy by John C. Mannone
The Solar-Ionospheric Connection: Physics
with the 20 MHz Antenna
At the 2003 SARA Conference, I discussed the increased utility of the 20 MHz radio telescopes. Systems, such as Radio Jove, can be an interesting probe for both solar physics and geophysics. A variety of resources are used to compare antenna signals originating from the sun. Simultaneous records from several different locations show similar gross features. However, there are differing finer details that present a challenge to reconcile. My new web page, http://home.earthlink.net/~jcmannone/, presents some very useful resources (Radio Astronomy Web Tools) that benefit any effort to understand comparisons of solar bursts (or Jovian storms).
In addition to these comparison tools, a frequency analysis of the antenna signals will reveal even more. There are many things that will affect a radio wave in its path to your antenna. Most notably is turbulence. It causes fluctuations in the solar wind and in our ionosphere. In turn, they cause the radio wave to fluctuate. Even upper level winds in our atmosphere can affect the radio wave in the same way starlight is made to twinkle.
These different kinds of twinkle can be studied by signal processing methods available in Microsoft Excel. The mathematic tool is called an FFT from which a power spectrum is plotted. It reveals these effects on the radio wave and points to the physics causing it.
Radio twinkling is usually studied with more sophisticated equipment and at much high frequencies (~250-1700 MHz) because of their importance in communication, navigation, and pulsar research. The exciting thing here is exploration of “new ground” with the 20 MHz systems; and, we have a virtual global antenna farm to do it with.