Information For
Comet Calendar Event Details
Hot Flow Anomaly: Explosions at the Earth's Bow Shock
Monday, Apr 8, 2013
4 p.m. - 5:15 p.m. Location: SLC 1.102

Dr. Hui Zhang
Geophysical Institute, University of Alaska Fairbanks

The Earth’s magnetic field carves out a cavity known as the magnetosphere in the solar
wind ejected from the Sun’s upper atmosphere. A bow shock standing upstream from the magnetosphere serves to decelerate and deflect the supersonic solar wind, enabling it to flow around the magnetosphere. In gasdynamic and magnetohydrodynamic models, no information about the interaction reaches the region upstream from the bow shock.
However, when kinetic effects are considered, hot flow anomalies (HFAs) form upstream
from the Earth’s bow shock. HFAs exhibit dramatic plasma heating (by a factor of 10)
and enormous flow deflections (sometimes even backward toward the Sun). Because
HFAs drive magnetopause boundary waves, modulate electron precipitation, trigger
auroral brightenings or dimmings, excite ULF waves within the magnetospheric cavity,
drive field-aligned currents, and initiate high-latitude ionospheric magnetic impulse
events, they are an essential aspect of the solar wind-magnetosphere-ionosphere
interaction and deserve detailed study. From a theoretical point of view, they provide a
fascinating example of local (microscale) effects having global effects. I will begin by
providing a basic introduction to the Earth’s magnetospheric environment, introduce
what are HFAs, why do we study them, and then describe outstanding questions about
HFAs, I will then discuss my work on particle heating inside HFAs, the evolution of
HFAs, and the discovery of Spontaneous HFAs (SHFA).

Contact Info:
Anton Malko,
Questions? Email me.

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