1. Simulations of Ionospheric Turbulence near the Upper Hybrid Layer
A. Najmi – University of Maryland
B. Eliasson – University of StrathClyde
X. Shao, G. Milikh, S. Sharma, K. Papadopoulos – University of Maryland

2. Introduction
Observation of DAILs (Descending Artificial Ionized Layers) (Pedersen et al 2009, 2011)
Model formation
Langmuir turbulence accelerates fast electrons
Suprathermal electrons ionize neutral gas at lower altitudes
Plasma becomes dense enough to absorb HF wave
Entire interaction region descends
Requires initial bulk of 4000K for effective Langmuir turbulence (Eliasson et al 2012)
Our Results:
UH Turbulence can produce bulk heating up to 6000K
Can also produce tail accelerations with average kinetic energy K
Mechanism: Bulk heating due to electron Bernstein waves, tail heating due to UH waves near gyroharmonic.

3. Objectives What is the mechanism for pre-heating LT?
How do these simulations compare with other experiments?
Stimulated Electromagnetic Emission (SEE) Ground-based measurements of electromagnetic radiation
Broad Upshifted Maximum (BUM) – associated with heating above 𝑁 𝜔 𝐶𝐸
Downshifted Maximum (DM) – associated with UH turbulence and 3-wave decay (UH -> UH + LH)
Pedersen et al. – GRL 2010
doi: /2009GL041895

4. Methods Vlasov Simulation Test Particle follow-up
Simulate distribution functions
Low noise
Keep wave modes as well
Shift background w/ pump to maintain UH resonance
Test Particle follow-up
Manipulate Wave Modes
Beeman Explicit Predictor-Corrector Algorithm
Test convergence with − particles

5. Wave Modes

6. Temperature

7. Test Particle Simulations - I

8. Test Particle Simulations - II

9. Test Particle Simulations - II
Pump
DM-01

10. SEE Features - I Simulation Results
Courtesy NRL:
Bernhardt, Briczinski,
Siefring.
BRIOCHE Campaign
2013
Simulation Results
Ground-Based SEE Receiver Measurements

11. SEE Features - II BUM Pump DM Simulation Results
Courtesy NRL:
Bernhardt, Briczinski,
Siefring.
BRIOCHE Campaign
2013
BUM
Pump DM
Simulation Results
Ground-Based SEE Receiver Measurements

12. Conclusions Observations: Mechanism:
Below the cyclotron resonance, heating at the UH layer can heat bulk electrons in striation to K
At and above resonance, the heating changes to a supra thermal acceleration, average kinetic energy up to K, distribution function is long-tailed.
Both are potentially useful for pre-heating Langmuir Turbulence
Mechanism:
Bulk heating driven by high-frequency, small-wavenumber components of the first electron Bernstein wave.
Supra thermal acceleration driven UH waves near 4 𝜔 𝐶𝐸