HAO Colloquium Series presents Lokesh Bharti, Mohan Lai Sukhadia, India

Time:  3:00–4:00 pmDate:  Wednesday, June 18, 2014Location:  CG1 – 2139 Captain Mary (no webcast or recording will be available)Title:  Opposite polarity and convective flows in simulated sunspot penumbra: comparison with observationsAbstract:Recent numerical simulations and observations of sunspot show significant amount of opposite polarity magnetic field in the penumbra. Most of the opposite polarity fields are associated with convective downflows. We present comparison to these quantities with observations from synthetic Stokes profiles of FeI 6301.5 Å and FeI 6302.5 Å lines for 3D MHD simulations. Syntectic Stokes profiles are spatially and spectrally degraded according to typical instrument properties. Line-of-sight velocities are determined from line bisector shifts for FeI 6301.5 Å line. Far wing magnetograms constructed from Stokes V profiles for FeI 6302.5 Å line. The fraction of opposite polarity- downflows and opposite polarity- downflow is strongly affected by spatial smearing. These quantities are robust with resolution in the simulations. I addition we use lines that form at different heights in photosphere in order to study the height variation of the Evershed flow .  We find that the results from line synthesis are in good agreement with observations.

Will this event be webcast to the public by NCAR|UCAR?: 
Announcement Timing: 
June 18, 2014