Simultaneous COMPTON GRO and optical monitoring of AGN

During two 14-day periods in January 1992 and March 1992, several AGN which have been in the wide field of view of COMPTEL and EGRET at that time were monitored optically for variations in intensity and polarization. We report on first results of this correlated optical and CGRO observations.     

Laboratory Tests of the Equivalence Principle at the University of Washington

Equivalence principle tests are probes for new fundamental physics. We have conducted several laboratory experiments to test the equivalence principle with unprecedented precision and generality using a torsion balance placed on a continuously rotating turntable. We present preliminary results comparing the differential accelerations of Ti, Be, and Al towards local masses, the earth and the center of our galaxy.     

Strategies for dealing with solar particle events in missions beyond the magnetosphere.

For long duration missions beyond the magnetosphere, the hazards posed by solar particle events (SPE) require the development of new strategies to minimize both the radiation dose and the effects. Potential strategies include the development of improved short-term forecasting of SPE through better observations and research, consideration of HZE particles in real-time forecasting and monitoring, improved knowledge of the biological effects of the particles involved in SPE, and the development of methods for combining SPE forecasts with temporary shielding and chemical countermeasures. Evaluation of present capabilities and the identification of areas of further research to achieve the necessary capabilities are discussed.     

Large-scale electric fields and currents and related geomagnetic variations in the quiet plasmasphere

At the end of the sixties it became obvious that two-dimensional dynamo models can explain nearly all facts, which had been found morphologically for mean annual Sq-fields. During the recent decade new or improved methods to measure electric fields (e.g. incoherent scatter facilities) and to investigate great data files have been developed. New informations received with these methods about the existence of regular variations of the Sq-field in dependence on season and universal time and about the electric field have been summarized in Section 2. All attempts to describe also these variations with a two-dimensional dynamo model did not lead to any success, but showed a strong theoretical over-estimation of the asymmetries. Therefore, it must be concluded that three-dimensional plasmaspheric current systems, taking into consideration the coupling between both hemispheres along the high-conducting magnetic field lines, are needed in order to explain the regular variations of the Sq -field. The basic equations for two- and three-dimensional dynamo models, different methods for the solution of these equations and the resulting models from different authors are compiled and discussed (Section 3).Based on all morphological and theoretical results a plasmaspheric-ionospheric current system has been constructed and some properties of the plasmaspheric field-aligned current distribution, have been derived.