Afven Speeds during the Afven Speeds during the January 20th, 2005 CMEJanuary 20th, 2005 CME

Pete RileyScience Applications International Corporation

What's the What's the significance of the significance of the

Alfven speed?Alfven speed?

Thermodynamic Thermodynamic MHD SolutionsMHD Solutions

•Energy equation, including coronal heating, thermal conduction, and radiation

•Driven by magnetogram from Carrington Rotation 2025

•Simulation advanced in time until steady-state reached

•Alfven speed computed from density and magnetic field strength

0

90

-90

0

180 360

Longitude

Lati

tude

Photospheric Magnetic Field

Longitude

Lati

tud

e

CME (from Gopalswamy et al., 2005)

VA near active region (0, 180)

Alfven speeds as a function of heightin vicinity of active region 720.

Some Caveats...Some Caveats...Ambient configuration != Pre-eruption config.Processed magnetograms reduce strength of

active regionsThermodynamic solutions are preliminary

=> density profiles approximateAlfven speed != fast-mode speed

Concluding Concluding RemarksRemarks

•MHD solutions suggest shock formation certainly possible within 1.2-1.5 Rs.

•Structure in equatorial plane suggests two regions on either side of AR where shock formation could occur earlier.

•These are our first attempts to model this time period with full thermodynamic code => caution with interpretation!