Electrostatic Tether Application for Scattering of Relativistic Particles in the Earth’s Radiation Belts

An electrostatic tether could be a recent technology application for removing energetic particles in the earth’s radiation belts. Both hollow cathode and high-voltage source will keep the conductive tether at high positive/negative bias. An effective Coulomb deflection of the particles into the loss cone will produce a high rate of atmospheric penetration, decreasing the amount of high-energy particles in the radiation belts. This paper focuses on the high positive-bias case with a sheath that is correctly modeled. For small radius and extremely high bias, the tether does collect the relativistic orbital motion limited current. Relativistic effects modify both potential and density profiles, decreasing the range of the sheath and, in turn, increasing tether current collection. The remediation time will increase if relativistic effects are considered. A remediation time of about six years is determined for 100 1-MV tethers moving in a circular equatorial orbit at an altitude of about 2000 km. In addition, the presence of both Coulomb and Lorentz forces may induce thrust or drag on the tether. Both forces are briefly studied with plasma condition characteristic of the inner radiation belt.