Review of quantitative models of the 0‐ to 100‐keV near‐Earth plasma

Quantitative modeling of the near‐earth plasma environment in the 0‐ to 100‐keV energy range has made significant strides in the last decade in response to the needs of spacecraft users and to the substantial improvements in the modeling of the earth's electric and magnetic fields. Concurrent with this has been an extensive growth in the observational data base necessary to evaluate these models. In this paper, models of the plasmasphere and near‐geosynchronous environment are reviewed and compared with the data; also discussed are potential users, their needs, and the ability of the models to meet those needs. The review indicates that although several significant problems are not resolved, quantitative low‐energy plasma models are at the stage that magnetic field models were at a decade ago and substantial gains are expected in the next few years.