Vlasov simulations of electron acceleration by radio frequency heating near the upper hybrid layer
Abstract
It is shown by using a combination of Vlasov and test particles simulations that the electron distribution function resulting from energization due to Upper Hybrid (UH) plasma turbulence depends critically on the closeness of the pump wave to the double resonance, defined as ω ≈ ωUH ≈ nωce, where n is an integer. For pump frequencies, away from the double resonance, the electron distribution function is very close to Maxwellian, while as the pump frequency approaches the double resonance, it develops a high energy tail. The simulations show turbulence involving coupling between Lower Hybrid (LH) and UH waves, followed by excitation of Electron Bernstein (EB) modes. For the particular case of a pump with frequency between n = 3 and n = 4, the EB modes cover the range from the first to the 5th mode. The simulations show that when the injected wave frequency is between the 3rd and 4th harmonics of the electron cyclotron frequency, bulk electron heating occurs due to the interaction between the electrons and large amplitude EB waves, primarily on the first EB branch leading to an essentially thermal distribution. On the other hand, when the frequency is slightly above the 4th electron cyclotron harmonic, the resonant interaction is predominantly due to the UH branch and leads to a further acceleration of high-velocity electrons and a distribution function with a suprathermal tail of energetic electrons. The results are consistent with ionospheric experiments and relevant to the production of Artificial Ionospheric Plasma Layers.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2017
- Source ID
- 10.1063/1.4999768
Entities
People
- A. Najmi
- A. S. Sharma
- B. Eliasson
- G. Milikh
- K. Papadopoulos
- Xuan‐Min Shao
Organizations
- Air Force Office of Scientific Research
- Directorate for Geosciences
- Engineering and Physical Sciences Research Council
- University of Maryland
- University of Strathclyde