Space Physics Seminar winter-2016

The Foremoon: A Complex Upstream Region of the Moon

As a consequence of the absence of shielding by a global magnetic field and a dense atmosphere, the Moon interacts directly with its ambient plasma. The classical picture of the Moon–-solar-wind interaction implies that the dayside lunar surface simply absorbs the incident charged particles, leaving a plasma void behind the Moon referred to as the "lunar wake." Although the upstream plasma and fields are not perturbed at all in this zeroth-order picture of the complete "passive absorber"–-solar-wind interaction, a variety of waves and modified particle-velocity distributions have been observed by a number of spacecraft in the upstream region magnetically connected to the Moon and to the lunar wake. In many respects, these lunar upstream waves and particles resemble those seen in the terrestrial foreshock. In this seminar, I will present an overview of this "foremoon," where multiple categories of Moon-related waves and particles coexist. I also show different characteristics of the Moon-plasma interaction in the solar wind, terrestrial tail lobes, and plasma sheet.