CARE: Rocket Experiments for Investigation of the Radar Scatter Proerties of a Dusty Plasma

Summary form only given. The Charged Aerosol Release Experiment (CARE) will use a rocket payload injection of particulates in the lower ionosphere to determine the mechanisms for enhanced radar scatter from the electrons imbedded in an artificial dusty plasma in space. Natural dusty plasmas in the mesosphere near 85 km altitude have been shown to enhance radar scatter at VHF frequencies by 40 dB or more. The CARE program is designed to study the scatter processes near 200 km altitude in the ionosphere where densities are up to 1000 times larger. Numerical simulations of particulate transport in the upper atmosphere with charging by electron pickup or photodetachment have been used to predict the dusty plasma densities. These charged particle distributions provide initial conditions for particle simulations of plasma turbulence driven by the free-energy of the high-speed charged particle motion. Finally, radar signals scattered from the plasma irregularities are estimated using electromagnetic wave theory. The physical properties of the dusty plasma as will be determined using the radar echoes as well as in situ probes on the rocket payload and on secondary payloads launched after the dust has settled into the lower atmosphere. In addition, the NASA AIM satellite will measure the dust layer by-scattered sunlight and absorption.