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Rudolf Komm
National Solar Observatory
Position
Department
Field of research
Natural Sciences (Astrophysics and Astrononmy)
Email
komm@noao.edu
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Large-Scale Subsurface Flows during Solar Cycle 23 and 24
Natural Sciences (Astrophysics and Astrononmy)
794 views
Date of upload:
03.09.2015
Co-author:
Rachel Howe, Frank Hill
Abstract:
We study the solar-cycle variation of the zonal and meridional flow in the near-surface layers of the solar convection zone from the surface to a depth of about 16 Mm. We have analyzed Dopplergrams obtained with the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO), the Global Oscillation Network Group (GONG),and the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) with a dense-pack ring-diagram analysis. The three data sets combined cover almost two solar cycles. The zonal and meridional flows vary with the solar cycle. Their amplitude variation tracks the mean latitude of activity and appears about three years before magnetic activity is visible in synoptic maps of the solar surface. We focus on the variation of the zonal and meridional flows, including their long-term variation at mid- and low-latitudes using GONG and MDI data and their variation at the high latitudes that are now accessible using HMI data. We will present the latest results.
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Subsurface helicity of active regions 12192 and 10486
Natural Sciences (Astrophysics and Astrononmy)
690 views
Date of upload:
04.09.2015
Co-author:
Sushant Tripathy, Rachel Howe, Frank Hill
Abstract:
The active region 10486 that produced the Halloween flares in 2003 initiated our interest in the kinetic helicity of subsurface flows associated with active regions. This lead to the realization that the helicity of subsurface flows is related to the flare activity of active regions. Eleven years later, a similarly enormous active region (12192) appeared on the solar surface. We plan to study the kinetic helicity of the subsurface flows associated with region 12192 and compare it to that of region 10486. For 10486, we have analyzed Dopplergrams obtained with the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO) and the Global Oscillation Network Group (GONG) with a dense-pack ring-diagram analysis. For 12192, we have analyzed Dopplergrams from GONG and the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). We will present the latest results.

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