The Day the Solar Wind Almost Disappeared

摘要

The sun emits a constant flow of charged particles into interplanetary space. On 11 May 1999, the number density of this "solar wind" decreased to remarkably low values (～0.2 particles/cm~3, compared with an average value of 10/par-ticles/cm~3). A special session of the American Geophysical Union 1999 Fall Meeting was devoted to discussing this extraordinary event and its consequences.