SCIENCE GOALS: THE TOTAL ELECTRON CONTENT (TEC) IS A CRITICAL IONOSPHERE STATE PARAMETER WITH SIGNIFICANT SPACE WEATHER IMPLICATIONS PRIMARILY AFFECTING COMMUNICATION AND NAVIGATION SYSTEMS. SUB-AURORAL POLARIZATION STREAMS (SAPS) ALSO KNOWN AS SUB-AURORAL ION DRIFTS (SAIDS) ARE FAST WESTWARD FLOWS IN THE IONOSPHERE THAT OCCUR AT LATITUDES LOWER THAN AURORAL PRECIPITATION AND WELL SEPARATED FROM THE HIGH-LATITUDE CONVECTION PATTERN. ALTHOUGH SAPS WERE FIRST OBSERVED IN THE IONOSPHERE THEY CAN ALSO BE SEEN IN THE MAGNETOSPHERE AND THEY ARE BELIEVED TO BE DRIVEN BY A COMBINATION OF REGION-2 CURRENTS AND LOW IONOSPHERIC CONDUCTANCE. SAPS ARE THUS GOVERNED BOTH BY MAGNETOSPHERE AND IONOSPHERE PROCESSES AND REQUIRE SELF-CONSISTENTLY COUPLED MODELS OF THE OUTER MAGNETOSPHERE THE INNER MAGNETOSPHERE AND THE RING CURRENT AND THE IONOSPHERE-THERMOSPHERE SYSTEM. IN CONJUNCTION WITH THE CONVECTION PATTERNS ASSOCIATED BY SAPS PLASMA WITH HIGH ELECTRON DENSITY IS CONVECTED BOTH SUNWARD AND UPWARD THROUGH THE CUSP AND FORMS A REGION OF STRONGLY ENHANCED TEC THAT EXTENDS OVER THE POLAR CAP CREATING STORM ENHANCED DENSITY (SED) AND THE TONGUE OF IONIZATION (TOI). OVER EXTENDED TIME PERIODS THE TOI CAN RECONNECT WITH THE CONVECTION PATTERN IN THE NIGHT SIDE. SED SAPS AND THE TOI ARE PRIMARILY STORM TIME PHENOMENA AND THEY PRODUCE DEPLETION AS WELL AS ENHANCEMENTS IN TEC. THUS UNDERSTANDING THE UNDERLYING PHYSICS AND DEVELOPING PREDICTIVE MODELS IS IMPORTANT.