Space Plasma Seminar

"High Resolution Global Magnetohydrodynamic Simulation of Bursty Bulk Flows" Mike Wiltberger, HAO/NCAR

March 3, 2015
4 pm - 5 pm
Location
200 Cummings Hall
Sponsored by
Thayer School of Engineering
Audience
Public
More information
Simon Shepherd
603-646-0096

Abstract:  A high-resolution global magnetohydrodynamic simulation is conducted with the Lyon-Fedder-Mobarry (LFM) model for idealized solar wind conditions.  Within the simulation results high-speed flows are seen throughout the magnetotail when the interplanetary magnetic field (IMF) is southward.  Case study analysis of these flows shows that they have an enhancement in BZ and a decrease in density preceding a peak in the flow velocity.  A careful examination of the structure within the magnetotail shows that these features are driven by bursts of magnetic reconnection.  In addition to the case study, a superposed epoch analysis of flows occurring during a 90 minute interval of southward IMF yields statistical properties that are in qualitative agreement with observational analysis of bursty bulk flows (BBFs).  The most significant differences with the observational results are a broader velocity profile in time and a larger density drop after flow passage.  The peak BZ amplitude is larger than in observations and precedes the peak in the flow velocity.  We conclude that the LFM simulations are reproducing the statistical features of BBFs and they are driven by spatially and temporally localized reconnection events within the simulation domain.

Location
200 Cummings Hall
Sponsored by
Thayer School of Engineering
Audience
Public
More information
Simon Shepherd
603-646-0096