STRUCTURE OF THE DISTANT GEOTAIL: ISEE-3 OBSERVATIONS (MAGNETOPAUSE, MAGNETIC MERGING, BOUNDARY LAYER, PLASMA SHEET)

We present the results of a theoretical and observational study of the distant geotail. The observations verify the following model predictions.;Similarly structured flux ropes are found deep within the magnetotail near the plasma sheet-lobe boundary. They are associated with tailward jetting hot plasma, high energy particles, strong broad band noise, auroral brightening, and disturbed ground magnetograms, and are therefore probably not related to RMFT's. Instead these ropes may be related substorms, and possibly to the field-aligned currents which produce omega bands.;In a twelve hour sequence of ISEE-3 multiple magnetopause crossings near the low-latitude dawnside magnetotail, the magnetopause normals pointed in the z-direction, boundary layer field lines bent in the y-direction, and the north lobe was observed south of the ecliptic plane. The boundary normals oscillated in a manner consistent with tailward moving waves on the southern boundary of the magnetotail. We interpret these phenomena as evidence for a twisted, flaring, and flattened magnetotail caused by a strong IMF B(,y).;A detailed statistical examination of magnetotail flattening shows that magnetosheath field lines deflect to pass around the magnetotail, producing the anisotropic magnetic pressure required for flattening. The predicted flattening should vary from less than 1 R(,E) near earth to 5 R(,E) at x = -200 R(,E), but the typical flattening observed is greater. The predicted flattening time scale (less than 1 hour) agrees well with that observed. A reinterpretation of simultaneous solar wind, near earth and distant magnetotail observations also suggests magnetotail flattening.;Flux Transfer Events (FTE's), flux ropes of connected magnetosheath and magnetosphere field lines, advect tailward from the dayside magnetopause with the magnetosheath flow. They lie drawn out nearly parallel to the magnetotail axis just outside the main body of the magnetotail, giving it a filamentary structure. Here we term the FTE's Reconnected Magnetic Flux Tubes (RMFT's) and recognize them by their location, boundary normals, magnetic field, and plasma characteristics.