David Schriver

Learn More
Observations by MESSENGER show that Mercury's magnetosphere is immersed in a comet-like cloud of planetary ions. The most abundant, Na+, is broadly distributed but exhibits flux maxima in the magnetosheath, where the local plasma flow speed is high, and near the spacecraft's closest approach, where atmospheric density should peak. The magnetic field showed(More)
[1] We have carried out a self-consistent three dimensional global hybrid simulation study examining the interaction of the solar wind with Mercury’s magnetosphere. We consider two cases: one with relatively high solar wind pressure, and another with relatively low solar wind pressure. With lower solar wind pressure, the subsolar magnetopause forms at about(More)
Solar wind energy transfer to planetary magnetospheres and ionospheres is controlled by magnetic reconnection, a process that determines the degree of connectivity between the interplanetary magnetic field (IMF) and a planet's magnetic field. During MESSENGER's second flyby of Mercury, a steady southward IMF was observed and the magnetopause was threaded by(More)
During MESSENGER's third flyby of Mercury, the magnetic field in the planet's magnetic tail increased by factors of 2 to 3.5 over intervals of 2 to 3 minutes. Magnetospheric substorms at Earth are powered by similar tail loading, but the amplitude is lower by a factor of approximately 10 and typical durations are approximately 1 hour. The extreme tail(More)
Pavel M. Trávnı́ček (trav@ig.cas.cz), Petr Hellinger (Petr.Hellinger@ig.cas.cz), and David Herčı́k, Institute of Atmospheric Physics, ASCR, Bocni II/1401, 14131 Prague 4, Czech Republic David Schriver, Institute of Geophysics and Planetary Physics, University of California Los Angeles, Los Angeles, 90095-1567, U.S.A., dave@igpp.ucla.edu James A. Slavin,(More)
[1] Several series of large dipolarization events are documented from magnetic field observations in Mercury’s magnetotail made by the MESSENGER spacecraft. The dipolarizations are identified by a rapid ( 1 s) increase in the northward component of the magnetic field, followed by a slower return ( 10 s) to pre-onset values. The changes in field strength(More)
Global measurements by MESSENGER of the fluxes of heavy ions at Mercury, particularly sodium (Na(+)) and oxygen (O(+)), exhibit distinct maxima in the northern magnetic-cusp region, indicating that polar regions are important sources of Mercury's ionized exosphere, presumably through solar-wind sputtering near the poles. The observed fluxes of helium(More)
[1] Analysis and interpretation of observations from the MESSENGER spacecraft in orbit about Mercury require knowledge of solar wind “forcing” parameters. We have utilized the Wang-Sheeley-Arge (WSA)-ENLIL solar wind modeling tool in order to calculate the values of interplanetary magnetic field (IMF) strength (B), solar wind velocity (V) and density (n),(More)
[1] MESSENGER’s January 14, 2008, flyby of Mercury has provided new observations of the planet’s magnetosphere for northward interplanetary magnetic field (IMF). The dusk magnetopause was located inward from the mean magnetopause surface, possibly due to reduced tail magnetic flux content for IMF Bz > 0 and/or the pressure of planetary pickup ions as they(More)
[1] We summarize observations by the MESSENGER spacecraft of highly coherent waves at frequencies between 0.4 and 5 Hz in Mercury’s inner magnetosphere. This survey covers the time period from 24 March to 25 September 2011, or 2.1 Mercury years. These waves typically exhibit banded harmonic structure that drifts in frequency as the spacecraft traverses the(More)