A 2D simulation study of Langmuir, whistler, and cyclotron maser instabilities induced by an electron ring-beam distribution

Journal Article · Thu Sep 15 00:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3626562· OSTI ID:22043476

Lee, K H; Lee, L C ^[1]; Omura, Y ^[2]

---

1. Institute of Space Science, National Central University, Taoyuan, Taiwan (China)
2. Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto (Japan)

We carried out a series of 2D simulations to study the beam instability and cyclotron maser instability (CMI) with the initial condition that a population of tenuous energetic electrons with a ring-beam distribution is present in a magnetized background plasma. In this paper, weakly relativistic cases are discussed with the ring-beam kinetic energy ranging from 25 to 100 keV. The beam component leads to the two-stream or beam instability at an earlier stage, and the beam mode is coupled with Langmuir or whistler mode, leading to excitation of beam-Langmuir or beam-whistler waves. When the beam velocity is large with a strong beam instability, the initial ring-beam distribution is diffused in the parallel direction rapidly. The diffused distribution may still support CMI to amplify the X1 mode (the fundamental X mode). On the contrary, when the beam velocity is small and the beam instability is weak, CMI can amplify the Z1 (the fundamental Z mode) effectively while the O1 (the fundamental O mode) and X2 (the second harmonic X mode) modes are very weak and the X1 mode is not excited. In this report, different cases with various parameters are presented and discussed for a comprehensive understanding of ring-beam instabilities.

• OSTI ID: 22043476
• Journal Information: Physics of Plasmas, Vol. 18, Issue 9; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM-PLASMA SYSTEMS
CYCLOTRON INSTABILITY
DISTRIBUTION
ELECTRON BEAMS
ELECTRON RINGS
EXCITATION
KEV RANGE 10-100
KINETIC ENERGY
MAGNETOHYDRODYNAMICS
MASERS
PLASMA SIMULATION
RELATIVISTIC PLASMA
RELATIVISTIC RANGE
RINGS
STREAMS
TAIL ELECTRONS
WHISTLER INSTABILITY
WHISTLERS