AMPAS — A new active experiment mission

Abstract

A new concept for an active experiments mission is presented: The Active Magnetospheric Particle Acceleration Satellite (AMPAS). It is proposed to fly a dual-payload tethered satellite to study three important areas of magnetospheric physics: (1) electric and magnetic field structures of the Earth's magnetosphere, (2) electron beam-plasma interactions, and (3) far ultraviolet (FUV) signatures of energetic electron precipitation. The tethered system is to be flown in a gravity-gradient stabilized configuration with a 70° circular orbit at altitudes in the range 300–800 km. The upper payload will carry two electron beam accelerators (1–10 keV, 1 A) and a plasma contactor to electrically neutralize the payload, while the lower payload will carry a complement of optical imaging and plasma diagnostics instrumentation. Upward directed beams are injected to “sound” electric and magnetic field structures, including parallel electric fields in the auroral region, while simultaneous optical instruments aimed downwards measure characteristics of reflected beam pulses precipitating into the upper atmosphere below the satellite. Downward directed beams, and simultaneous plasma wave, particle and optical measurements, are used for the investigation of beam-plasma interactions and electron precipitation studies. The payloads are to be connected by a 1–6 km long tether to be deployed in stages. The configuration of the beam source and the plasma and optical diagnostics on separate, tethered payloads allows the diagnostics to be performed outside of the disturbed region around the source payload, and plasma wave and particle observations of beam-plasma interactions to be performed at well-defined locations relative to the source.