View
29
Download
0
Category
Tags:
Preview:
DESCRIPTION
Physics and Measurements of Stimulated Electromagnetic Emissions. Paul A. Bernhardt, Stan Briczinski Plasma Physics Division Naval Research Laboratory Washington, DC 20375 University of Maryland 8 November 2011. Studying the Ionosphere with Active Experiments. - PowerPoint PPT Presentation
Citation preview
Physics and Measurements of Stimulated Electromagnetic Emissions
Paul A. Bernhardt, Stan BriczinskiPlasma Physics Division
Naval Research LaboratoryWashington, DC 20375
University of Maryland8 November 2011
Studying the Ionosphere with Active Experiments
• Active Experiments with High Power Radio Waves
– Frequency Range (2.6 to 10 MHz)– Global Distribution of HF Facilities
• Physics of High Power Radio Waves– Density, Temperature, Composition, and Irregularities
– Active Technique• Field Aligned Irregularity Glow with HF Excitation
• Stimulated Electromagnetic Emissions (SEE)
– Plasma Wave Generation and Propagation
• Research Inspired by Uppsala University– Low Frequency– OAM HF Beam Interactions
• Dissertation Defense
The Ionosphere Described by NRL SAMI3 in 2010
• Ref.: Huba, Krall, Joyce, SAMI3, 2010
• Plasma Density: 103 to 106 cm-3
• F-Layer Electron Temp.: 500 to 3000 K (0.05 to 0.3 eV)
• F-Layer O+ Ion Temp.: 500 to 2000 K
• Magnetic Field Strength: B0 ≈ 28 10-6 T
• Plasma Pressure Versus Magnetic Pressure
≈ nkT/(B2/20) = 10-8
• Ion Collisions Versus Ion Gyro Orbits
i ~ i at 100 km Altitude
Past, Current and Future HF Ionospheric Modification Facilities
Jicamarca
Arecibo Conjugate
F-Region Ionosphere
Stimulated Electromagnetic Emissions,Radar Backscatter, Enhanced Plasma Waves and Artificial Aurora
HF Radar HAARP Transmitter HF Receiver HF Receiver UHF Radar Camera
Plasma Physics of Ionospheric Modification withHigh Power Radio Waves
High PowerElectromagnetic
Wave Beam
ElectronTemperature
Elevation
PlasmaIrregularityFormation
ElectrostaticWave
Generation
PlasmaPressure and
DensityChanges
EnhancedRadarScatter
ParametricDecay and
StrongTurbulence
VLF Ductsand
ConductivityModification
LowFrequency
Waves
VLF Waveguides
and VLFGeneration
ModeConversion
HighFrequency
Waves
ElectronAcceleration
ArtificialAurora
StimulatedElectro-
magneticEmissions
Plasma Line
Ion Line
HF Antenna for Receiving Stimulated Electromagnetic Emissions from HAARP
Real Time Display of Stimulated Electromagnetic Emissions near HAARP with the MARK-IID Receiver
ES and EM Wave Generation
Optional ModeConversion
EM Pump Wave
High Power
EM or ES Wave
ParametricDecay
Optional ModeConversion
High Frequency EM or ES
Wave
Received EM Wave
Low Frequency ES Wave
Loss
Loss
Loss
Possible ModeConversion ?
Low Frequency EM Wave
DM
2DM
3DM
UM
BUM
Pump
In Situ Source: Upper Hybrid Waves
In Situ Source: Electron Bernstein
Modes
4.10 4.15 4.20 4.25 4.30
-10
-20
-30
-40
-50
-60
Frequency (MHz)
Rel
ativ
e P
ower
(dB
)
HAARP HF Transmitter Array2.6 to 10 MHz, Up to 3.6 GW Effective Radiated Power
Heater Power Beam Angle Sweeping
IAIA & EIC
Norin et al., 2009 observed the IA emission lines f1 and f2 due to Simulated Brillouin Scatter; Bernhardt et al.,2009 observed IA lines f1 and 2010 observed IA line f1 and EIC lines f3 ; Bernhardt, P. A., C. A. Selcher, and S. Kowtha (2011), Electron and ion Bernstein waves excited in the ionosphere by high power EM waves at the second harmonic of the electron cyclotron frequency,
Geophys. Res. Lett., 38, L19107, doi:10.1029/2011GL049390. The experiment conducted at HAARP in July, 2010 aims to look more thoroughly at a broader range of heater beam angle effects on IA and EIC waves generated by MSBS (Fu, Scales, Bernhardt 2011).
I: Vertical beam (0o,0o)II: Zenith beam (14o ,202o)
(28 o, 202 o) (28
o , 22
o )
Vertical
Magnetic Zenith
11
Generalized MSBS matching conditions
0
2 2 1/ 20
2 20
For O mode reflected at
1For X mode reflected at [ ( 4 ) ]
2
The upper hybrid resonance is
p
ce ce pe
UH ce pe
-f4 -f3 -f2 -f1
Reflection
Upper hybrid
[Bernhardt , 2009 ]
f1- IA at reflection region;f2- IA at upper hybrid; f3- EIC at reflection region;f4- EIC at upper hybrid; 12
-18
0 H
z
-12
0 H
z
12
0 H
z
18
0 H
z
Stimulated Brillouin Scatter with Ion Acoustic Wave Generation is Simple
EM1
IA1
EM2
SBS-1
B
Pum
p
SB
S-1
f IA1
= 0
B
Brillouin Scattering of the 4.5 MHzHAARP Vertical Beam
in the Ionosphere
SBS with EIC Generation Yields Ion MassO
ffse
t F
requ
ency
(H
z)
Radio Beam Angel with B ()
B
f EIC
-1
f IA-1
111.1 Azimuth 16.3 Zenithmi = e B/fEIC = m[O+]
fEIC-1
fIA-1
-18
0 H
z
-12
0 H
z
12
0 H
z
18
0 H
z
Set II : Experimental Results for 4.1 MHz, O-mode Full Power, UT 04:15:00-04:60:00,07/22/2010
(Haiyang Fu, Virginia Tech)
•The IA lines f1=10~12 Hz is stronger close to the magnetic zenith •The IA lines f2=24~26 Hz appears for ZA=28o, AZ=202o •The EIC lines f3=50~52 appears for ZA=28o, AZ=202o •The newly observed f4=70~72 appears for ZA=28o, AZ=202o
f1=10~12 Hz; f2=24~26 Hz; f3=50~52 Hz;f4=70~72 Hz;
16
Stimulated Ion Bernstein (SIB) Generation by Tuning to the Second Electron Gyro Frequency
EM0 EB0FAI
IB1
EB1
EM1
FAI
SIB1
IB2
EB2
EM2
FAI
SIB2
IB3
EB3
EM3
FAI
SIB3
Stimulated Ion Bernstein Waves with f0 = 2 fce
• HF Tuned to 2nd Electron Cyclotron Harmonic
• Ion Cyclotron Frequency = 55 Hz
• Dropout of Ion Cyclotron Mode
• Constant Amplitudes for Ion Bernstein Modes
• Observed at All Pointing Angles
• Search for Narrowband Ground ELF Signal
Direct ULF Generation
• Process– HAARP 3.6 MW HF transmitter– High Gain Phased Array Antenna
12 x 15 Dipoles Each Excited by 20 kW Phased to Tilt HF Beam Greater than 20 Degrees from B
– Frequency Tuned Away from Gyro Harmonic (4.2 MHz) Decay of Pump Wave
Electrostatic Ion Cyclotron Wave Downshifted EM Wave
Coupling of EIC wave to ULF EM Mode on Field Aligned Irregularities
– Detection with Ground Receivers UFL Receiver Tuned to About 48 Hz HF Receiver Tuned to 4.2 MHz with 250 kHz BW
• Results– EIC Mode Second Strongest Produced– Strong Dependence of HF Beam Orientation
F-Region Ionosphere
Stimulated ULF and HF Electromagnetic Emissions with HAARP
HAARP Transmitter ULF ReceiverHF Receiver
HAARP Array Generates a Hollow Beam
Antenna Gain (dB)
22
Artificial Ionospheric Layers Created by the HAARP Transmitter
HF Twisted Beam
Layer 1Layer 2
Frequency (MHz)
Alti
tude
(km
)
• Objectives– Form Stable Plasma Layer
– Open Artificial Propagation Path
• Progress– Demonstrated Twisted Beam
– Formed Layer Lasting 5 Minutes
– 4th Harmonic Resonance
– Cyclotron Resonance Theory
23
SEE Near the 4th Gyro Harmonic and Artificial Layers
25 March 2011 00:53:00 UT
25 March 2011 00:51:30 UT
Layer Produced for 4.5 Minutes
03:3
2:00
-1 0 1 2 3 4 Seconds
3.2 MHz
+50 kHz
-50 kHz
-100 kHz
26 August 2011 SEE 03:32 UT
27 August 2011 SEE00:04
UT
0 1 2 3 4 5 6 Seconds
6.1 MHz
+100 kHz
+200 kHz
+300 kHz
-300 kHz
-200 kHz
-100 kHz
00:0
4:00
HF SEE Receiver Use Conclusions
• Simple New Experiments for HAARP• 4th Gyro Harmonic Heating with Twisted Beam
– Broad Upshifted Maximum and Ion Bernstein Waves in SEE Obtained with the Mark II-D Receivers
– Long Lasting Artificial Plasma Layers at Fixed Altitude
• Coordinated Receiver Observations– HF SEE Modes Measured with the Mark II-D Receivers
– ULF Ground Modes
• Acknowledgments– NRL Support by Geoff San Antonio and Serafin Rodriquez
– MIT Lincoln Support by Scott Coutts and Matthew Morris
• Future Work – Plasma Science Instruments in Space– HF Receiver
– Langmuir Probe
– Magnetometer
Recommended