Strategic Characteristics of Dynamics Explorer. 1. Retarding Ion Mass Spectrometer and the Consequences for Core Plasma Measurements
Abstract
The Retarding Ion Mass Spectrometer (RIMS) on the Dynamics Explorer I (DE I) satellite has provided a new range of data, and challenges for studies of the core plasma of the magnetosphere. Analysis of the RIMS data provides a measure of the satellite potential in the inner magnetosphere. As the satellite leaves the inner plasmasphere, it begins to charge positively, crossing the 0 V mark at about 1000/cc. The potential rises slowly initially, reaching about 1 V near the plasmapause, at the 100/cc point. At lower densities, the potential rises relatively rapidly, reaching +5 V or greater at the 10/cc point. For satellite potentials of +1 to +5 V, portions of the ion distribution function are lost to measurement because the ions are repelled by the satellite. In particular, in a multi-temperature plasma, the cold component is easily lost in this potential (density) regime. It is in this regime where aperture bias techniques have been successfully used, particularly in measurements of field- aligned ion flows such as the polar wind, which have sufficient kinetic energy to overcome electrostatic barriers in front of the aperture plane. At lower densities (<10/cc), the satellite potential can exceed +5 V. At such potentials the core plasma is lost to the RIMS, and even the aperture bias techniques are no lower successful. Keywords: Spacecraft charging; Thermal plasmas; Mass spectrometry.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 14, 1989
- Accession Number
- ADA214013
Entities
People
- R. C. Olsen
Organizations
- Naval Postgraduate School