This proposal describes a study of electrodynamic processes and auroral physics in the polar ionosphere. The scientific goals for this project are in the area of polar ionospheric electrodynamics and magnetospheric energetic particle acceleration.. Specific topics of focus and interest are the size, frequency and mechanisms of relativistic electron precipitation events from the ionosphere into the magnetosphere. The experiment involves three axis double probe electric field experiments that the University of Houston has been invited to provide to the UC Berkeley MINIature Spectrometer MINIS payloads to be launched simultaneously from SANAE and McMurdo Stations, Antarctica in December 2003 and January 2005. The payloads will also contain X ray detectors and science magnetometers with sufficient sensitivity to study geomagnetic micropulsations. The University of Houston portion of the work includes construction of the electric field instrumentation, leading the McMurdo part of the field operations in Antarctica, and data analysis and interpretation. The specific objectives of this proposal are: 1.~Construct 5 three-axis double probe electric field detectors suitable for use on high altitude balloon payloads. 2.~Integrate these experiments into the MINIS payloads at UC Berkeley. 3.~Conduct testing and evaluation of the payloads. 4.~At the end of year one and the start of year 2, conduct flight operations in Antarctica. 5.~In years 2 and 3, reduce, analyze and interpret the data. 6.~In year 3, participate in a data analysis worksop at UC Santa Cruz.