Simulation of plasma emission in magnetized plasmas
arXiv:2109.11663 · doi:10.3847/1538-4357/ac32bb
Abstract
The recent Parker Solar Probe (PSP) observations of type III radio bursts show that the effects of finite background magnetic field can be an important factor in the interpretation of data. In the present paper, the effects of background magnetic field on the plasma emission process, which is believed to be the main emission mechanism for solar coronal and interplanetary type III radio bursts, are investigated by means of the particle-in-cell simulation method. The effects of ambient magnetic field are systematically surveyed by varying the ratio of plasma frequency to electron gyro-frequency. The present study shows that for a sufficiently strong ambient magnetic field, the wave-particle interaction processes lead to a highly field-aligned longitudinal mode excitation and anisotropic electron velocity distribution function, accompanied by a significantly enhanced plasma emission at the second harmonic plasma frequency. For such a case, the polarization of the harmonic emission is almost entirely in the sense of extraordinary mode. On the other hand, for moderate strengths of the ambient magnetic field, the interpretation of the simulation result is less than clear. The underlying nonlinear mode coupling processes indicate that to properly understand and interpret the simulation results require sophisticated analyses involving interactions among magnetized plasma normal modes including the two transverse modes of the magneto-active plasma, namely, extraordinary and ordinary modes, as well as electron-cyclotron-whistler, plasma oscillation, and upper-hybrid modes. At present, a nonlinear theory suitable for quantitatively analyzing such complex mode-coupling processes in magnetized plasmas is incomplete, which calls for further theoretical research, but the present simulation results could provide a guide for future theoretical efforts.
arXiv comment14 pages, 8 figures. This paper will be submitted to Astrophysical Journal(ApJ)
References in corpus (17)
- A Review of Solar Type III Radio Bursts
- Emission of Type II Radio Bursts - Single-Beam versus Two-Beam Scenario
- Dynamics of electron beams in the solar corona plasma with density fluctuations
- Dynamics of electron beams in the inhomogeneous solar corona plasma
- Statistics and Polarization of Type III Radio Bursts Observed in the Inner Heliosphere
- Nonlinear Wave Interactions as Emission Process of Type II Radio Bursts
- Self-consistent particle-in-cell simulations of fundamental and harmonic plasma radio emission mechanisms
- Density fluctuations and the acceleration of electrons by beam-generated Langmuir waves in the solar corona
- Particle-in-cell and weak turbulence simulations of plasma emission
- Conditions for electron-cyclotron maser emission in the solar corona
- How Electron Two-Stream Instability Drives Cyclic Langmuir Collapse and Continuous Coherent Emission
- Langmuir Wave Electric Fields Induced by Electron Beams in the Heliosphere
- A comparison of weak-turbulence and PIC simulations of weak electron-beam plasma interaction
- Wave excitation by energetic ring-distributed electron beams in the solar corona
- Harmonic radio emission in randomly inhomogeneous plasma
- PIC Simulation of Double Plasma Resonance and Zebra Pattern of Solar Radio Bursts
- An alternative form of the fundamental plasma emission through the coalescence of Z-mode waves with whistlers