Generation of plasma waves by a Tethered Satellite System with satellites elongated in the direction of flight for arbitrary oblique geometry

Abstract

One of the effects of the coupling of a tethered satellite system to the ambient plasma is the excitation of plasma waves in the Earth's ionosphere. The generation of wave wings has been described by various authors using linear theory to investigate the electrodynamical behavior of a conducting body in a moving magnetized plasma. In this paper an analytical description of these waves including oblique geometry is given by extending the perpendicular geometry model of Estes (1988) with satellites elongated in the direction of flight. We include the case of fully arbitrary geometry, i.e., the magnetic field, direction of flight, and direction of the tether are not perpendicular to each other. We derive far‐field equations for the magnetic field aligned current density and the associated wave impedance where a two‐dimensional Fourier transform has to be done numerically. We find that the limits of the frequency bands for propagating waves (Barnett and Olbert, 1986) change due to changes in the geometry of the magnetic field. Our calculations are limited to the lowest band, i.e., frequencies below the ion cyclotron frequency. The solution for the far field can be described as wave wings which are tilted by a small angle dependent on the system's velocity and the Alfvén velocity. For the associated wave impedance we find strong dependence on the geometry of the magnetic field.