Estimating radiated power from a conducting tethered satellite system

Abstract

In anticipation of the upcoming TSS‐1 experiment, theoretical calculations are made of radiated power from a conducting tethered satellite system. The radiation results from the steady motion of the system through the ionospheric plasma and it is stimulated by collection and emission of charge by the noninsulated surfaces of the tethered end connectors. A model of the current system is developed which incorporates the tether wire, satellite surfaces, and sheath currents. The radiation impedance of the current model is calculated using the previously developed theory of Barnett and Olbert (1986). The results confirm the low‐frequency Alfvén wave description with a predicted radiation impedance of a few tenths of an ohm in the Alfvén wave limit. Calculations are also made in the lower hybrid and whistler wave band. A larger impedance of ∼13 Ω is found for the frequency range ∼5–50 kHz. By estimating the passive ion current drawn by the system a prediction of the total radiated power is also made. The result of 0.38 mW raises the question of whether or not wave emissions from a passive current collecting system may be detectable by either ground‐ or space‐based platforms.

The dynamics of low‐β plasma clouds as simulated by a three‐dimensional, electromagnetic particle code

“…For dense beams a virtual systems generated in the ambient plasma as a result of large cathode will form in the beam at a point where the beam orbiting structures and large plas•na clouds have therefore electrons stagnate as their velocity away from the spacecraft much in common. The radiation from large space strucis reduced, due to the electrostatic forces in the beam and tures have been studied by Donohue et al [1991], current the spacecraft, which charges to positive potentials [ Winglee closure and radiation for large clouds have been treated anand Pritchett, 1988;Pritchett, 1991]. The virtual cathode alytically by Borovsky [1987], and current closure and wave allows only a fraction of electrons to escape the spacecraft; generation for large space structures have been studied in however, some of the escaping electrons may have energies laboratory plasma tanks by Stenzel and Urrutia [1990].…”

Ionospheric wave emissions passively detected by the OEDIPUS A Tether

“…This possibility was first investigated by Drell et al [1965] with reference to Alfv6n waves which propagate at frequencies below the ion cyclotron frequency (--•40 Hz). More recent work [Barnett and Olbert, 1986;Hastings et al, 1988;Wang and Hastings, 1991;Donohue et al, 1991] has shown that radiation may also arise in the whistler and Z modes already discussed above.…”

Tether radiation in Juno-type and circular-equatorial Jovian orbits

“…It was suggested by Estes [1988], Donohue et al [1991], and Sanmartin and Martinez‐Sanchez [1995] that the characteristic lengths of the cloud emitted by an active contactor or the sheath radius on a passive contactor might be larger than the dimensions of the end‐contactor itself; nonlinear effects would adjust contactor areas to an effective value (paper 1) where j th ≡ eN e ( k B T e /2 πm e ) 1/2 is the unperturbed random current density, with T e ≃ 46 eV and the density profile N e in the inner plasmasphere given by .…”

“…Pioneer work on the plasma waves radiated by a conductive tether in low Earth orbit (LEO) was carried out by Drell et al [1965]. This work was followed by later authors [ Barnett and Olbert , 1986; Dobrowolny and Veltri , 1986; Hastings and Wang , 1987, 1989; Estes , 1988; Donohue et al , 1991; Sanmartin and Martinez‐Sanchez , 1995] (hereinafter referred to as paper 1) considering the cold plasma approximation. Recently, Biancalani and Pegoraro [2010b] considered radiation by a loop current inside a satellite orbiting in LEO, and Sanchez‐Torres et al [2010] (hereinafter referred to as paper 2) carried out a preliminary study of the Alfvén impedance of a tether in a Juno‐like orbit at the Jovian magnetosphere.…”