HR: 0800h
AN: SH32A-0790    [Abstracts]
TI: Validation of Far-side Imaging of Solar Active Regions through Numerical Simulations
AU: * Hartlep, T
EM: thartlep@mail.arc.nasa.gov
AF: NASA Ames Research Center, M/S N230-2, Moffett Field, CA 94035,
AU: Zhao, J
EM: junwei@solar2.stanford.edu
AF: W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305,
AU: Mansour, N N
EM: nagi.n.mansour@nasa.gov
AF: NASA Ames Research Center, M/S N230-2, Moffett Field, CA 94035,
AU: Kosovichev, A G
EM: sasha@quake.stanford.edu
AF: W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305,
AB: Helioseismology provides important tools for understanding the solar interior as well as for space weather forecast. Using observation data from instruments such as MDI (Michelson Doppler Imager) aboard the SOHO (Solar and Heliospheric Observatory) spacecraft, helioseismic inferences have tremendously advanced our knowledge and understanding of the interior structure and dynamics of the Sun. In general, the methods used for analyzing observations are based on simplified models of wave propagation such as ray or Born approximation, but have not been validated by more sophisticated models or numerical simulations.
Here, we evaluate one technique, far-side imaging of solar active region by time-distance helioseismology, by using artificial oscillation data derived from numerical simulations of wave propagation in the Sun. The simulations are performed for the full spherical Sun. Active regions are modeled by locally modifying the speed of sound. We evaluate the performance of the far-side imaging technique by varying the size and location of the artificial active region, and analyse the appearance of ghost images and artifacts.
This research is supported by NASA's Living with a Star program. The support ot the NASA Postdoctoral Program administered by Oak Ridge Associated Universities is gratefully acknowledged. Simulations have been performed on the Columbia Supercomputer at NASA Ames Research Center.
DE: 7522 Helioseismology
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting