Time-variable phenomena in the magnetosphere and exosphere of Mercury

The possibility of transient particle acceleration in Mercury's magnetosphere during substorm-like events is considered. The case of dipolarization effect is simulated by making use of a simple analytical model. It is shown that protons and alpha particles could be accelerated to a few tens of keV if the corresponding dipolarization time scale is on the order of 10 sec. Impulses of sodium clouds from surface sputtering might consequently be generated with comparable time scale.