INJECTION OF SHEAR ALFVEN WAVES IN THE INNER RADIATION BELT USING ARECIBO

Dennis PapadopoulosUniversity of Maryland, College Park

The Seventeenth Annual RF Ionospheric Interactions Workshop

17-20 April 2011Santa Fe, New Mexico

Acknowledge Contributions:UMCP: Xi Shao, B. Eliasson, S. SharmaBAE Systems AT: C.L.Chang, I. Doxas, J. Lebinsky

MHD MODES

MHD WAVES - MS

MAGNETO-SONIC MS

€

ω /k = VA ,ω /kz = VA cosθ

Q ≡∇⊥⋅r E ⊥= 0

M ≡∇⊥×r E ≠ 0

MHD WAVES - SA

SHEAR ALFVEN (SA)

€

ω /kz = VA , r V g = VA

ˆ b

M ≡ (∇⊥×r E ⊥)⋅ ˆ b = 0

Q ≡∇⊥⋅r E ≠ 0

k

E

B

b

Svg

FAC

IONOSPHERIC MHD PROPAGATION

RESONATORS AND

DUCTS

Propagation SA Waves – Ionospheric Alfven Resonator (IAR)

)( hVn A

R

ω

k

E

B

b

SvgSA wave is guided along the B field

Reflections create standing wave structure

Noticeb·B=0

Natural SA waves

Fabry-Perot like Resonator

Cash et al. 2006

Reflection due to grad h

kE1

Bo

Magnetosonic Alfven Wave (compressional)

Bo

Propagation MS Waves Alfvenic Duct

D/E Region Ejet

F-peak

SA and MS wave Equations

€

ε∂∂t

+ σ P

⎛ ⎝ ⎜

⎞ ⎠ ⎟Q = −σ HM −

∂Jz

∂z, ε

∂∂t

+ σ P

⎛ ⎝ ⎜

⎞ ⎠ ⎟M = σ HQ −

1μ0

∇2Bz +1B0

∇⊥2 δp⊥,

∂Bz

∂t= −M , μ0

∂Jz

∂t= −

∂Q∂z

+∇⊥2 Ez , ε 0

∂∂t

+ σ ||

⎛ ⎝ ⎜

⎞ ⎠ ⎟Ez = Jz , .

€

ε(z) =c2

VA2(z )[1 +ν in

2 (z )/ Ωi2 ]

€

Q =∇⊥⋅ E⊥, M = ∇⊥ × E⊥( )⋅ i z , Jz = (∇⊥ × B⊥)⋅ i z

SAW M=0MS Q=0

Lysak 1998

MS-SW Wave CouplingLow Latitude Pc1

1.AIC instability due to proton anisotropy drives SA waves at high L-shells

2. SA partly mode converted by Hall to MS propagate in Alfvenic duct to lower latitude

3. Ground signature due to Hall current driven by the MS interaction with E-region

KEY OBSERVATION: NO SAW OR EMIC WAVES IN INNER RB AND SLOT

.1-5 Hz

RADIATION BELTS

REGIONSPARTICLE LIFETIMES

Wave particle Interactions (WPI) Pitch Angle Diffusion (PAD)

Radiation Belts – Inner - Outer

Protons Electrons

PARTICLE FLUX LEVEL -> BALANCE OF INJECTION TO TRANSPORT AND PRECIPITATION (WPI) RATE Pitch angle diffusion (PAD)

slot

WPI-PAD CONTROL OF LOSS RATE

ULF/ELF/VLF waves resonate with trapped particles in the magnetosphere causing pitch angle scattering and precipitation. B0

trapped

€

ω −kzvz = nΩkzvz ≈ ±Ω

Inner Proton Belt

Typical inner belt proton lifetimes: 10 MeV – decades50 MeV – century

SA Wave BoundaryNo SA Waves

Proton Lifetimes in the Inner Belt are Long

Typical inner belt proton lifetimes: 10 MeV – decades100 MeV – centuries1000 MeV – millennia

South Atlantic Anomaly

Over the south Atlantic, the inner proton belt is closest to the surfaceProtons in this region are the largest radiation source for LEO satellites

MAJOR RESEARCH OPPORTUNITY

ACTIVE CAUSE AND EFFECT PROBING OF THE INNER BELT

Active Probing of Inner RB Using the Arecibo Heater

Arecibo

South Atlantic Anomaly

RBSP

WPI critical aspect of RB physics. RBSP will study interactions in the natural environment, A wave injection facility at Arecibo at frequencies that resonate with energetic protons and electrons offer cause and effect understanding of the induced transport processes with RBSP

Focus on SAW for protons

and EMIC for electrons

Frequency Selection for ProtonsExample for L=1.5

2

( , )cos 2

z p

z A

A

k V

k V

MVEE

ω

ω

ω

Frequency Selection for Resonance of Protons with SAW

Fill tube with SAW

Frequency requirement for equatorial resonance with SAW at L=1.5

Frequency range 5-30 Hz

2 22 2 3

21

2 2

2

/

1( | |) ( )

for

As a result 1/ / before

reaching resonance (1/ 0)

z z e

pe pj

je j

j

z e z

z

k v

k c

k c

k v

k

ω ωωω ω ω ω

ωω

ENERGETIC ELECTRON WP INTERACTIONS DUE TO EMIC WAVES

Summers et al., 1998, 2000, 2003

Outer Belts

Frequency Selection for Electrons EMIC

Summers et al., 1998, 2000, 2003

Outer Belts

For midlatitude MeV electronsHelium

branch

HOW TO INJECT SA AND EMIC WAVES FROM

ARECIBOHAARP PEJ VS. ICD

n<<e

n>>e

J

Hall

JPedersen

Bo

SA Wave Generation During Electrojet PEJ Anenna

en

εω

/ /P H en e

en e

J J

T

n

n

E

+ +

+ +

+

+ +

+ +

+

I I I

I I I

I

Eo

Injects whistlers and SAW

heater

E

H

TEM mode

Near field Far field

FAC 0<t<T

0 T<t<2ToE E

E

T

Bottom of the ionosphereεω

MHD Wave Generation by the PEJ

• SA waves can be detected: (a) In the near zone below the heated spot and (b) By satellites over-flying the heated spot but confined to the magnetic flux tube that spans the heated spot (c) Through the EI waveguide for f>8 Hz (Schumann Resonance)

PEJ

SA will be guided by the magnetic field to the conjugates – No lateral

propagation through the plasma

Evanescent in EI Waveguide if f<8Hz

/ 2 8Ef c R Hz Schumann

ULF Signal Propagation Evanescent Mode (1 Hz)

• 28 April, 2007 UTC 05:01:00 – 05:05:45• HAARP at 2.88 MW and 3.3 MHz• Detected 1 Hz & 3 Hz peaks• B~1/R2 wave evanescent (Frequencies below Schumann

Resonance)

9.9 pT .28 pT

Gakona Juneau – 800 km

Frequency .2 Hz

Closest distance 80 km

Detection time 25 sec

Detection distance 150 km

1.5 pT on the ground

SAW DEMETER Detection

BeforeAfter

.2 Hz

Excitation of the IAR due naturally excited waves at .25 Hz and .5 Hz and by HAARP generated SA at 1.0 Hz.

IAR Excitation by the PEJ

MS Wave

Ionospheric Current Drive (ICD) Concept

2 exp( )B pJ i tB ω

Step 1:

Step 2: E field of MS wave drives Hall current in E-region resulting in secondary antenna resembling PEJ

Injects SAW upwards and ELF in the Earth-Ionosphere Waveguide

Model of CID for Vertical B

€

ε∂∂t

+ σ P

⎛ ⎝ ⎜

⎞ ⎠ ⎟Q = −σ HM −

∂Jz

∂z, ε

∂∂t

+ σ P

⎛ ⎝ ⎜

⎞ ⎠ ⎟M = σ HQ −

1μ0

∇2Bz +1B0

∇⊥2 δp⊥,

∂Bz

∂t= −M , μ0

∂Jz

∂t= −

∂Q∂z

+∇⊥2 Ez , ε 0

∂∂t

+ σ ||

⎛ ⎝ ⎜

⎞ ⎠ ⎟Ez = Jz , .

€

ε(z) =c2

VA2(z )[1 +ν in

2 (z )/ Ωi2 ]

€

Q =∇⊥⋅ E⊥, M = ∇⊥ × E⊥( )⋅ i z , Jz = (∇⊥ × B⊥)⋅ i z

Lysak 1998

Cylindrical Coordinates

MS SAW

Papadopoulos et al. GRL 2011

10 Hz

Secondary Antenna Current and Ground Field

Jq

Br

2 Hz2 Hz

ICD vs. PEJ How to Distinguish2 kHz as ejet proxy

102

103

1040

0.2

0.4

0.6

0.8

1

1.2A

vera

ge F

ield

Lev

el N

orm

aliz

ed to

2 k

Hz

frequency [Hz]

3.3 MHz Heating

EISCAT 2002 HAARP

B (2 kHz)

B(U

LF)/B

(2kH

z)

.5

ICD

PEJ

Papadopooulos et al. GRL 2005

ICD PoP

Chang et al GRL submitted

ICD Further PoP Tests

Electrojet Modulation

Current Drive

(Gakona) ULF VS 1 kHz Amp.All Times [04/28/2008 21:00:00 - 05/04/2008 09:20:00]

1 kHz Amplitude (pT)

0.0 0.5 1.0 1.5 2.0 2.5

ULF

Am

plitu

de (p

T)

0.0

0.5

1.0

1.5

2.0

2.5

(Gakona) ULF VS 1 kHz Amp.All Times [04/28/2008 21:00:00 - 05/04/2008 09:20:00]

1 kHz Amplitude (pT)

0.0 0.5 1.0 1.5 2.0 2.5

ULF

Am

plitu

de (p

T)

0.0

0.5

1.0

1.5

2.0

2.5

5/2008

9/2009

Ejet Current Strength

Proof of Concept ICD Experiment – Conducted under DARPA/BRIOCHE

Chang-Lebinsky-Milikh-Papadopoulos

2.8 MHz, O-mode

Msonic Wave Injection

10 sec oscillations

.1 Hz

DEMETER

Two site measurements - ICD vs. PEJ

350 km away

PEJ

ELF detection at Distant Sites

• Distance to Gakona– Lake Ozette, WA (W)

• 1300 mi– Hawaii (H)

• 2900 mi– Guam (G)

• 4800 mi• Detection under quiet Gakona cond.• No detection during electrojet days

Oct. 22-23

Implications of ICD to RB and RBR – Potential Arecibo Tests

Eliasson-Papadopoulos: Oblique model includes spontaneous B field generation

Bt (c /ne)n T

HF heating

SAW injection

Papadopoulos and Chang GRL, 1985

B

Ground B field

B field at 90 km

Ganguly-Gordon-Papadopoulos PRL 1985

ICD provides explanation for puzzling Arecibo experiment

Summary

• HAARP experiments have helped transition ofof cartoon HF low frequency current drive in the ionospheric plasma to reality.

• The physics understanding of ICD provided by HAARP allows for active probing of the physics controlling the inner radiation belt and could lead to techniques that can actively reduce the flux of trapped proton and electrons.