Electromagnetic Ion Cyclotron Waves for Radiation Belt Remediation Applications

Abstract

The high-energy particles of the Van Allen belts coming from cosmic rays, solar storms, and man-made processes pose a risk to humans and spacecraft operating in those regions. These high-energy fluxes rapidly damage electronics, optics, and other systems. The radiation belt remediation (RBR) concept has been proposed as a way to solve this problem through ULF/VLF transmissions in the magnetosphere capable of precipitating these energetic particles into the atmosphere. This paper analyzes the effect of an RBR in-situ transmitter on inner belt energetic protons and outer belt electrons. This interaction requires the radiation of the left-hand polarized electromagnetic ion cyclotron (EMIC) band from space-borne antennas. The transmitter driving frequency and radiation pattern characteristics needed to drive the interaction are analyzed and applied to the calculation of individual test particles' scattering for different radiated power levels. The results show that the effect of the transmitter on individual loss cone particles is up to three orders of magnitude smaller for inner belt protons than outer belt electrons. While protons' scattering scales linearly with the wave field amplitude, electrons' scattering rapidly saturates because particles are being lost into the atmosphere. A radiated power flux of 10-9 W/m2 at the source would require three days of continuous interaction to scatter near loss cone inner belt protons by 1°, and 0.2 s in the case of outer belt electrons. If we increase the radiated power flux to 10-5 W/m2, this interaction is reduced to 30 s for protons and 35 milliseconds for electrons. The engineering feasibility of EMIC transmitters is finally discussed; plasma contactors at both ends of a linear dipole antenna and magnetic loop arrangements are identified as possible EMIC in-situ transmitter solutions.