Study on antenna characteristics for wave observation including kinetic effects of space plasma

点击翻译按钮获取中文摘要

The objectives of the current study is to acquire the quantitative understanding of antenna characteristics in a magnetized space plasma by performing three-dimensional electromagnetic PIC simulations, which will be helpful designing the antenna onboard the future scientific satellite. We first examined the plasma sheath effect to the antenna impedance. We found that the sheath effect on the antenna impedance become weak when the radius of ion sheath formed around the antenna in the isothermal plasma becomes large. Next, we studied a case in which photo-electrons are emitted from the antenna surface. It is found that antenna impedance is affected at the frequency corresponding to the high density of photo-electrons in the vicinity of antenna. We finally examined a hot plasma case and found that the resonance at the plasma frequency becomes less sharp. Another important factor in the antenna characteristics is the effective length which is related to the current distribution along the antenna. In the receiving mode of antenna, however, the current distribution depends on the load impedance attached to the antenna and therefore the effective length may be modified. We will examine the dependency of the effective length on the load impedance as well as the plasma environment including plasma sheath, photo-electron emission, and finite temperature of plasma by performing EM-PIC simulations.