HR: 1330h
AN: SH22A-0177    [PDF]
TI: $I+LCT:$ A Method for Determining Photospheric Flows from Magnetograms
AU: * Welsch, B T
EM: welsch@ssl.berkeley.edu
AF: Space Sciences Lab, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450
AU: Fisher, G H
EM: fisher@ssl.berkeley.edu
AF: Space Sciences Lab, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450
AU: Abbett, W P
EM: abbett@ssl.berkeley.edu
AF: Space Sciences Lab, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450
AB: Coronal mass ejections (CME's) are magnetically-driven reconfigurations of plasma in the low-$\beta$ solar corona; they are the primary drivers of space weather. One way to investigate coronal field evolution before and during such events involves driving MHD simulations of the coronal magnetic field using data from time series of vector magnetograms. Doing so requires specification of a three-component velocity field at the simulated photosphere, consistent with the observed magnetic field evolution in that layer. Unfortunately, such velocity data are not generally available. We have developed a method that finds photospheric plasma velocities consistent with both the flows derived by the familiar techinique of local correlation tracking (LCT), and the field evolution described by $z$-component of the induction equation. We present results obtained by applying this ``$I+LCT$'' technique to vector magnetograms, and to ``false'' magnetograms obtained from MHD simulations of photospheric field evolution.
DE: 7524 Magnetic fields
DE: 7529 Photosphere
DE: 7594 Instruments and techniques
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting