Nascap-2k Simulation of a Low-Frequency Antenna in Low-Earth Orbit.

摘要

NASCAP-2K can be used to calculate plasmadynamic effects as well as steady-state charging and current collection. In this paper we consider electron dynamics in the sheath of a VLF antenna. We estimate the sheath size, and show 1-D calculations for both sine wave and square wave excitation. The results show strong electrostatic plasma oscillations at the sheath edge. Then we use NASCAP-2K to approach the problem from 2 directions. Run as explicit Particle-in-Cell, NASCAP-2K can duplicate the square wave results through the first maximum in the plasma oscillation, obtaining excellent agreement with the 1-D results. Due to the computational demands of PIC, this approach can only simulate the early transients using a common PC. To learn more about the floating potential of the antenna, NASCAP-2K can be run as hybrid PlC to capture the ion dynamics over the full wave cycle.