SARA Regional ConferenceSARA Regional Conference

Arecibo Radio ObservatoryArecibo Radio ObservatoryPuerto RicoPuerto Rico

December 10-12, 2004December 10-12, 2004

Application of Spectral AnalysisApplication of Spectral Analysisfor Amateur Radio Astronomers:for Amateur Radio Astronomers:

Probing the Sun-Earth Connection Probing the Sun-Earth Connection

John C. MannoneJohn C. Mannone

Visiting Professor of Physics and AstronomyVisiting Professor of Physics and AstronomyTamke-Allan ObservatoryTamke-Allan Observatory

&&Consulting Nuclear Chemical Safety AnalystConsulting Nuclear Chemical Safety Analyst

Duke, Cogema, Stone & Webster, LtdDuke, Cogema, Stone & Webster, Ltd

Supporting ResearchersSupporting Researchers

Wanda Diaz, University of Puerto Rico, San JuanWanda Diaz, University of Puerto Rico, San Juan

David Fields, Director of the Tamke-Allan David Fields, Director of the Tamke-Allan ObservatoryObservatory

Bill Howe, Computer ConsultantBill Howe, Computer Consultant

Abstract Abstract

Examples of spectral analysis techniques for the Examples of spectral analysis techniques for the amateur astronomer are demonstrated with Excel. amateur astronomer are demonstrated with Excel. Sunspot and magnetometer data (interplanetary Sunspot and magnetometer data (interplanetary magnetic field (ACE satellite) and geomagnetic magnetic field (ACE satellite) and geomagnetic field (GOES satellite)) as well as decametric field (GOES satellite)) as well as decametric antenna signals are analyzed in context of the Sun-antenna signals are analyzed in context of the Sun-Earth connection; especially ionospheric Earth connection; especially ionospheric phenomena.phenomena.

A brief update on the status of plasma bubble A brief update on the status of plasma bubble research is presented. This includes plans for the research is presented. This includes plans for the construction of an inexpensive fluxgate construction of an inexpensive fluxgate magnetometer as well as improved data magnetometer as well as improved data acquisition and computer processing. acquisition and computer processing.

SUN SPOT CYCLESSUN SPOT CYCLESSOLAR OBSERVATORY OBSERVATIONSSOLAR OBSERVATORY OBSERVATIONS

The number of sunspots on the visible solar surface

Counted by many solar observatories

Averaged into a single standardized quantity- sunspot number, R

Daily index of sunspot activity R = k(10g +s) wheres = number of individual spots g = number of sunspot groupsk is an observatory factor (= 1 for the Zurich Observatory; adjusted for all others to obtain approximately the same R)

Once derived at Zurich (see Wolf number) Rz; now at Brussels

RI is widely distributed smoothed sunspot number (since 1981) This number has been determined from data back to 1620 (some regularity since 1700 and on a strict daily basis since 1849)

85.3

11.1 years

9.8

8.55.4

51.2

Excel ToolsData Analysis

Fourier Analysis (FFT)

limited to 2N data points (… 256, 512, 1024, 2048, or 4096)

304 annual sunspot data points => require two overlapping power spectra

The results are virtually identical

85.3

11.1 years

9.8

8.55.4

51.2

Spectral analysis of the Sunspot Numbers and Meteorological Parameters 

1. Classical Fast Fourier Transform (FFT) 

2. Maximum entropy method (MEM) 

3. Lomb-Scargle periodogram method including (optionally) a fast evaluation scheme

4. CLEAN deconvolution method, including the possibility to reconstruct time series from the derived spectral components in an integrated computational step

5. Autoregressive method of the spectral analysis (ARMA) 

Comparison of power spectra for different methods. 

Sunspot Cycle using 160 years of Daily Sunspot Numbers

(56,900 data points from the archives of the Royal Society of Belgium)

Note the 11-year sunspot cycle is very apparent, but solar cycle length and the intensity variation over the long 88-yr period (Gleissberg) are not as obvious, but are extracted with spectral analysis

11 years

88 years

Solar Rotation Frequency From FFT of Daily Sunspot Numbers

Butterfly diagram show sunspot distribution symmetric about solar equator +/- 35 degrees

Expect rotation period band from sunspot numbers time average equatorial period close to 25.6 days.

The 26.9 days is within experimental and model errors (FFT algorithm and axis of tilt)

Solar Rotation Period and other Short Cycles

Solar Cycles found in Meteorological Indices27, 13-14, 9, and 6-7 day

Earth’s Magnetic Field disturbances6 and 9 day

Simulating the Mechanism of the Action of Heliophysical Parameters on Atmospheric Processes 

Geofisica Internacional,April 1997 J. Pérez-Peraza1, A. Leyva1, I. Ya. Libin2, V. Fomichev2, R. T. Guschina2, K. Yudakhin2 and A. Jaani3

  1 Instituto de Geofísica, UNAM, México.   2 IZMIRAN, Troitsk, Moscow Region, Russia.   3 Estonian Meteorological and Hydrological Institute, Tallinn, Estonia.  

Abstract: With the aim of developing prediction techniques of meteorological and climatological phenomena we develop a simulation of the mechanisms of influence of heliophysical parameters on atmospheric parameters. The physical mechanism of the influence of solar and geomagnetic activities and other cosmophysical factors on the behavior of the weather, pressure, Earth's temperature, precipitation, atmospheric circulation, and stormicity is reviewed. The different mechanisms of the influence of solar activity (SA) on meteorological and climatological parameters and on the behavior of experimental meteorological and climatological data at different cycles of the SA are also discussed. The behavior of experimental data is compared with the predictions of theoretical models of the influence of SA on the lower atmosphere: our results indicate a relationship between the variations of atmospheric parameters and variations of galactic (GCR) and solar (SCR) cosmic rays and atmosphere transparency. The predictions of different scientific works in the field of helioclimatology are analyzed, and it is shown that Pudovkin's model of the influence of SA on the lower atmosphere is correct. Finally, a method for the prediction of the different meteorological and climatological parameters using previous data on them as well as on SA, GCR

and SCR is proposed. 

WHAT THE SUNSPOT RECORD TELLS US ABOUT SPACE CLIMATE Submitted to Solar Physics 2004/08/31 DAVID H. HATHAWAY and ROBERT M. WILSON NASA/Marshall Space Flight Center/NSSTC, Huntsville, AL 35812

Abstract: The records concerning the number, sizes, and positions of sunspots provide a direct means of characterizing solar activity over nearly 400 years. Sunspot numbers are strongly correlated with modern measures of solar activity including: 10.7-cm radio flux, total irradiance, x-ray flares, sunspot area, the baseline level of geomagnetic activity, and the flux of galactic cosmic rays. The Group Sunspot Number provides information on 27 sunspot cycles, far more than any of the modern measures of solar activity, and enough to provide important details about long-term variations in solar activity or “Space Climate”

” The sunspot record shows: 1) sunspot cycles have periods of 131±14 months (10.9±1.2 yrs) with a normal distribution; 2) sunspot cycles are asymmetric with a fast rise and slow decline; 3) the rise time from minimum to maximum decreases with cycle amplitude; 4) large amplitude cycles are preceded by short period cycles; 5) large amplitude cycles are preceded by high minima; 6) although the two hemispheres remain linked in phase, there are significant asymmetries in the activity in each hemisphere; 7) the rate at which the active latitudes drift toward the equator is anti-correlated with the cycle period; 8) the rate at which the active latitudes drift toward the equator is positively correlated with the amplitude of the cycle after the next; 9) there has been a significant secular increase in the amplitudes of the sunspot cycles since the end of the Maunder Minimum (1715); and 10) there is weak evidence for a quasi-periodic variation in the sunspot cycle amplitudes with a period of about 90 years. These characteristics indicate that the next solar cycle should have a maximum smoothed sunspot number of about 145±30 in 2010 while the following cycle should have a maximum of about 70±30 in 2023.

INTERPLANETARY MAGNETIC FIELD INTERPLANETARY MAGNETIC FIELD ACE MAGNETOMETERACE MAGNETOMETER

ACE Level 2 Data Summary by Instrument

* CRIS: Galactic Cosmic Ray Element Fluxes * EPAM: Solar Particle Fluxes * MAG: Interplanetary Magnetic Field Parameters * SEPICA: Solar Energetic Particle Element Fluxes * SIS: Solar Energetic Particle, Low Energy

Galactic Cosmic Ray, and Anomalous Cosmic Ray Fluxes

* SWEPAM: Solar Wind Parameters * SWICS/SWIMS: Temperatures and Speeds of

Solar Wind Ions, and Solar Wind Species Ratios * ULEIS: Solar Suprathermal and Energetic

Particle Fluxes

The MAG Instrument on ACE

The Magnetic Field Experiment (MAG) consists of twin vector fluxgate magnetometers controlled by a common CPU. The sensors are mounted on booms extending 4.19 meters from the center of the spacecraft at opposite sides along the +/-Y axes of the spacecraft. The instrument returns 6 magnetic field vector measurements each second, divided between the two sensors, with onboard snapshot and FFT buffers to enhance the high-frequency resolution.

Interplanetary Magnetic Field DataMAG level 2 data is organized into 27 day time periods (Bartels Rotations - roughly one solar rotation period). For each Bartels Rotation, the level 2 data contains time averages of the magnetic field data over the following time periods:

* 16 seconds* 4 minutes* hourly* daily* 27 days (1 Bartels rotation)

Quiet and Active Periods during the Sunspot Maximum

ACE Interplanetary Magnetic FieldDays 192 to 201 (mid July) 2000

North component

IMF is quiet during the solar maximum; FFT 4096 point Power Spectrum is featureless- essentially a corresponding delta function (or its approximation by the sinc function- sinx/x)

(sampling frequency corresponds to 16 seconds between samples or 62.5 millihertz)

IMF is indicating storming during the solar maximum; FFT 4096 point Power Spectrum has features- solar waves in the wind have periods in the order of hours (18.2, 4.6, 3.0, 1.1, 0.53) with moderate to strong amplitude (energy)

IMF is not indicating storming, but may be experiencing some disturbance; FFT 4096 point Power Spectrum has features- solar waves in the wind have periods in the order of hours with one strong amplitude (1.4 hr), but the majority are substantially weaker (energy) (4.6, 2.3, 1.1, 0.86, 0.70 hr)

IMF is not indicating storming, but may be experiencing some disturbance; FFT 4096 point Power Spectrum has features- solar waves in the wind have periods in the order of hours with strong doublet amplitude (3.6, 2.6 hr), and some weaker (energy) ones (1.8, 1.5, and 1.1)

(A sudden enhanced disturbance was noted that day)

During solar minimum the Sun's magnetic field, like Earth's, resembles that of an iron bar magnet, with great closed loops near the equator and open field lines near the poles. Scientists call such a field a “dipole." The Sun's dipolar field is about as strong as a refrigerator magnet, or 50 gauss. Earth's magnetic field is 100 times weaker.

During the years around solar maximum (2000 and 2001 are good examples) spots pepper the face of the Sun. Sunspots are places where intense magnetic loops -- hundreds of times stronger than the ambient dipole field -- poke through the photosphere. Sunspot magnetic fields overwhelm the underlying dipole; as a result, the Sun's magnetic field near the surface of the star becomes tangled and complicated.

The Sun's magnetic field isn't confined to the immediate vicinity of our star. The solar wind carries it throughout the solar system. Out among the planets we call the Sun's magnetic field the "Interplanetary Magnetic Field" or “IMF." Because the Sun rotates (once every 27 days) the IMF has a spiral shape -- named the “Parker Spiral” after the scientist who first described it.

Above: Steve Suess (NASA/MSFC) prepared this figure, which shows the Sun's spiraling magnetic field from a vantage point ~100 AU from the Sun.

Earth has a magnetic field, too. It forms a bubble around our planet called the magnetosphere, which deflects solar wind gusts. (Mars, which does not have a protective magnetosphere, has lost much of its atmosphere as a result of solar wind erosion.) Earth's magnetic field and the IMF come into contact at the magnetopause: a place where the magnetosphere meets the solar wind. Earth's magnetic field points north at the magnetopause. If the IMF points south -- a condition scientists call "southward Bz" -- then the IMF can partially cancel Earth's magnetic field at the point of contact.

Southward Bz's often herald widespread auroras, triggered by solar wind gusts or coronal mass ejections that are able to inject energy into our planet's magnetosphere.

"When Bz is south, that is, opposite Earth's magnetic field, the two fields link up," explains Christopher Russell, a Professor of Geophysics and Space Physics at UCLA. "You can then follow a field line from Earth directly into the solar wind" -- or from the solar wind to Earth. South-pointing Bz's open a door through which energy from the solar wind can reach Earth's atmosphere!

TERRESTRIAL MAGNETIC FIELDTERRESTRIAL MAGNETIC FIELDGOES MAGNETOMETERGOES MAGNETOMETER

GOES SEM MissionSEM in the Big Picture

NOAA operates a series of meteorology observing satellites known as Geosynchronous Operational Environmental Satellites (GOES). Even though the weather pictures from GOES are seen nightly in our living rooms via the local weather broadcast, few people know that GOES also monitors space weather via its onboard Space Environment Monitor (SEM) system. The three main components of space weather monitored by GOES at 35,000 Km altitude are: X-rays, energetic particles, and magnetic field.

Magnetometer

A twin-fluxgate spinning sensor allows Earth's magnetic field to be described by three mutually perpendicular components: HP, HE and HN. HP is parallel to the satellite spin axis, which is itself perpendicular to the satellite's orbital plane. HE lies parallel to the satellite-Earth center line and points earthward. HN is perpendicular to both HP and HE, and points westward for SMS-1, SMS-2, GOES-1, GOES-2, GOES-3, and GOES-4, and eastward for later spacecraft (like GOES 6 here). HE and HN are deconvoluted from the transverse component HT. Field strength changes as small as 0.2 nanoTesla can be measured.

Magnetometer (cont.)

The magnetometer samples the field every 0.75 seconds (1333mHz). Four of these values constitute a frame and are sent to the ground station together.

The data here is averaged in 60 second intervals (16.7 mHz)

Data availability

online data plotting capabilities1974 and the present (GOES series)

Spin rate 100 RPM

or 16,667 mHz

Name GOES 6 (GOES-F)Orbit type GEO at longitude:

* 135° W (28/04/1983-29/07/1984)* 98° W (29/07/1984-12/11/1994)Operator NOAALaunch date/time28 April 1983 02:26:00 UTCInstrumentInstrument SEM (Space Environment Monitor)Data coverage01/1986 - 11/1994Data resolution5-minute averagedPI EPS: Herbert H. Sauer (SEL/NOAA)X-ray monitor: Howard A. Garcia (NOAA)Dan Wilkinson (NGDC/SPIDR)Source SPIDRL-coverage 6.5 - 7.5 REData setVariable DescriptionAltitude Fixed value: 35790 kmLatitude Fixed value: 0°Longitude Interpolated from daily averagesMeasured B Magnetometer dataHp Magnetometer dataHe Magnetometer dataHn Magnetometer data

Time Series of GOES 6 Magnetometer Data

Approaching solar maximum; FFT 1024 point Power Spectrum

(sampling frequency corresponds to 60 seconds between samples or 16.7 millihertz)

resonant frequency, mHzresonant frequency, mHz power, dBpower, dB

0.070.07 38.7438.74

0.160.16 31.8831.88

0.310.31 29.0129.01

0.550.55 24.3324.33

0.960.96 19.4319.43

1.641.64 18.8118.81

2.212.21 16.5216.52

2.802.80 15.7415.74

3.353.35 14.4314.43

3.893.89 19.2519.25

4.444.44 13.9713.97

5.005.00 14.8314.83

5.555.55 8.588.58

6.096.09 10.2510.25

6.646.64 6.806.80

7.237.23 7.327.32

P = af-2

(f > 1 mHz)

Clearly not random noise nor typical of geophysical spectra behavior,which follows 1/f (according to Kevin Kilty, but I have not confirmed this)

RADIO SCINTILLATIONRADIO SCINTILLATION20 MHz ANTENNA SIGNALS20 MHz ANTENNA SIGNALS

Solar Bursts, Jovian Emissions, and Solar Bursts, Jovian Emissions, and Galactic NoiseGalactic Noise

Radio Spectraof Various Sources

Adapted from Fig. 6.2 Atmospheric Window and Sky Brightness (NRAO library)

Frequency, MHz20

p = -0.65

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)

GEOMAGNETIC PERTURBATIONSGEOMAGNETIC PERTURBATIONS PLASMA BUBBLES & SUDDEN PLASMA BUBBLES & SUDDEN

ENHANCEMENT DISTURBANCESENHANCEMENT DISTURBANCES

20 MHz ANTENNA SIGNALS 20 MHz ANTENNA SIGNALS

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

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

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.

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

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.

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

MAGNETOMETER DESIGNMAGNETOMETER DESIGN

The fluxgate is one kind of magnetic field sensor which combines good sensitivity with relative ease of construction. The basic principle is to compare the drive-coil current needed to saturate the core in one direction as opposed to the opposite direction. The difference is due to the external field. Full saturation is not necessary; any nonlinearity will do. As the core approaches saturation, the signal picked up in the sense coil will show the nonlinearity. For instance, if you put a sine-wave into the drive coil, the sense coil would detect harmonics of the fundamental frequency; increasing in strength relative to the fundamental as the core becomes more fully saturated. You can also drive with a square wave (easier to generate) and look at asymmetries in the sense coil output. If you are interested in building a fluxgate yourself, I recommend the 1991 article in EW+WW [1].

I have drawn above a quick sketch of the windings of a toroidal-core, single-axis fluxgate: that is, it responds to the magnetic field vector along the indicated axis of sensitivity. Note that the red wire (drive coil) is wound closely around the core, passing through the central hole on each turn. The blue wire (sense coil) is wound around the outside and does NOT pass through the central hole at all. I have drawn a few windings for clarity but in practice, for best sensitivity, both drive and sense windings might have 100 turns or more. With this type of core you can get two orthogonal axes of sensitivity for almost the price of one, just by winding another sense coil over the first but at right angles (the wires would run horizontal in the picture above, and the axis of sensitivity would be up-and-down.)

You can also make a single-axis with a simple rod core: in this case you wind the sense and drive coils over each other (or side by side) and you can get only one sensing axis (along the core) per fluxgate.

Almost any metal or ferrite will do for the core; when you want good sensitivity then you use special high-mu materials. I happened to use a random core from Haltek Electronics in Sunnyvale, CA (36 mm OD, 8 mm thick, partly copper-clad, marked "2299926-2C AL729").

For those interested, I provide an outline of the circuit I used to make a fluxgate. This is a simplified version of the article's [1] circuit with a non-optimal core; even so, I was able to pick up fluctuations in the earth's field of 20 gammas or so. Since the ambient field is fluctuating at least that much constantly, it's hard to determine if you have better sensitivity unless you have an active nulled Helmholtz-coil system to provide a more stable local field, or a magnetically-shielded room (which I didn't have). I was able, for instance, to see clearly someone rolling a

metal cart through the hallway about three meters away.

FGM3-Sensor by Speake & Co. Ltd., UK www.speakesensors.com Download Datasheet(MS-Word.doc)

Karsten Hansky (DL3HRT) and Dirk Langenbach (DG3DA) devellopped this kit Trough the AKM-Forum für Polarlichter (german) this Project became also known by the visual aurora chasers. In the mean time the prototype (Picture 1) has been turned into a more professional kit that can be easily build by others. The measurements are comparable to the professional magnetometers, especially if one takes the simplicity of the equipment in account.

The complete electronics ( Microcontroler, real-time clock, in- and output , two analogue outputs and keyboard-,LCD- and RS-232 Interfaces) are all have their place on the 100x100 mm doublesided printed circuit board (Picture 2).

The key board is on a small separate printed circuit board. No exotic components or smd techniques were used. Below a picture of the finished magnetometer: Picture 3

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 Poetry

John C. MannoneDec 8, 2004

On the Spectrum of Things About the Sun

Sunspots

Like twirling overcooked spaghettimagnetic field lines twist and breakin hot swirling plasmaGiant hurricanes anchor the broken strandsfor a whilebut the constant churning, year after yearincites a riotA heated outrage breaks outevery decade or solike a labor union with an agenda on a time clockor maybe it’s just an adolescent sunthat flares up when its face gets blemished by all those spots.

Sunstruck

The Sun, struck like a bell with multiple toneseach clamor to be heardcacophony swept as static in solar wind, like seaswooshLegacy of coronal tunesecho in the surf washing on our shorePauseContemplate the crests, the swirlsthose that mesmerize, beckonlike ocean waves inviteto plunge the coolof nature’s rhythmsAllow the seduction…of the mind.

Sunwhispers

A Type II tidal waverushes towards Earth a million miles an hourSometimes the sun quakes and spits out its vaporized lava like some angry volcano godThank the real God for magnetic coats that work like asbestos onesBillions of tons of fire water crash and bend the shieldA few sneak through and burn the sky with purple shimmerMost squeeze the fieldSending ripples down its spineLike dominos that fall into each otherripples wiggle into every thing, our planetThe storm transformsto the kind that doesn’t need a metaphorto the kind that’s wet with furyto the kind that’s sweet with spring

I wonder what El Nino is whispering todayWhisperingIn a small still voicewhispering…

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.