On March 31 and April 1, 1979, a sequence of substorms was recorded on the ground. During the entire active period the ISEE 1 and 2 satellites were located in the magnetotail, between 22 RE and 12 RE from the earth. Observations of plasma distributions made at varying levels of activity during these substorms provide good examples of typical magnetotail responses. These measurements were obtained with the University of Iowa LEPEDEA on board the ISEE 1 spacecraft. While the entire magnetotail undergoes temporal variations during substorm activity, the most obvious effect seen is spatial motion of preexisting plasma regimes, for example, at substorm onset the central plasma sheet contracts. This can cause a spacecraft to move from the plasma sheet into the boundary layer. As the plasma sheet boundary layer almost always comprises streaming plasma, the high-speed flows observed there are not necessarily due to the substorm process. We find that the essential nature of the main plasma regions of the magnetotail is relatively unchanged during high activity. ¿American Geophysical Union 1987