Showing papers by "Lou-Chuang Lee published in 1984"
TL;DR: In this paper, the authors studied the reflection and transmission of small amplitude magnetohydrodynamic (MHD) waves of solar-wind origin through the earth's open magnetopause and found that depending on the type of incident wave, the incident angle and the orientation of the ambient magnetic field, the amplitudes of the emanating waves can be amplified.
Abstract: Reflection and transmission of small amplitude magnetohydrodynamic (MHD) waves of solar-wind origin through the earth's open magnetopause are studied. The open magnetopause with a nonzero normal component of magnetic field is assumed to be a rotational discontinuity. For any of the incident waves, there is one reflected wave (fast magnetosonic wave) and five transmitted waves (one fast magnetosonic wave, two slow magnetosonic waves, one Alfven wave and one entropy wave). In this paper, cases with different incident waves, i.e., Alfven wave, fast magnetosonic wave, forward slow magnetosonic wave and entropy wave are studied. It is found that depending on the type of incident wave, the incident angle and the orientation of the ambient magnetic field, the amplitudes of the emanating waves can be amplified. The research findings also suggest that the transmission of MHD waves across the rotational discontinuity at the earth's magnetopause can be an important mechanism for the energy transfer from the solar wind into the magnetosphere.
40 citations
TL;DR: In this article, the linear growth and nonlinear saturation of electromagnetic radiation amplified by a hot (5-20 keV) population of electrons possessing a loss cone velocity distribution in the presence of a cold (20-500 eV) electron population are studied.
Abstract: The linear growth and nonlinear saturation of electromagnetic radiation amplified by a hot (5-20 keV) population of electrons possessing a loss cone velocity distribution in the presence of a cold (20-500 eV) electron population are studied. A relativistic electromagnetic simulation code is used to study the emission process. Three cases are presented in detail to illustrate the generation process of auroral kilometric radiation. The first case, which has an electron plasma frequency omega(pe) = 0.2 omega(ce) (electron cyclotron frequency) and possesses a double loss cone distribution, exhibits a strong narrow peak of the fast extraordinary mode (X mode) radiation just above the X mode cutoff frequency. The second case with omega(pe) = 0.2 omega(ce) and a single loss cone distribution shows a preferred direction of propagation for the amplified radiation. The third case with omega(pe) = 0.5 omega(ce) shows a peak in the ordinary mode (O mode) radiation. In all cases, the radiation saturates by turbulent scattering of resonant particles into the loss cone.
35 citations
TL;DR: In the presence of the helium ions, the variation in the traveling time of the unstable waves is typically 5-20 min, which is comparable to the duration of some of the observed IPDP events as mentioned in this paper.
Abstract: The IPDP pulsations are assumed to be generated in the region where the low-density energetic protons (10–100 keV) injected during substorms encounter the high-density plasmasphere. The increase in the wave frequency during the IPDP events is proposed to be caused by the enhanced dispersion of the wave velocity due to the presence of the helium ions in the plasmasphere. In the presence of the helium ions, the variation in the traveling time of the unstable waves is found to be typically 5–20 min, which is comparable to the duration of some of the observed IPDP events.
7 citations
TL;DR: In this paper, the dimensional analysis of the energy transfer from the solar wind to the magnetosphere is formulated to include the effect of finite lifetime of the ring current particles, and it is found that the solar-wind energy input rate should be re-evaluated by considering the life cycle of the rings current particles.
2 citations