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  • Measuring the magnetic energy and helicity in the emerging active regions with HMI vector magnetograms

     

    Seminar Title:

    Measuring the magnetic energy and helicity in the emerging active

     regions with HMI vector magnetograms

    Speaker:

    Dr. LIU Yang

    Affiliation: 

    (Stanford University)

       

    When:

    Wednesday morning, Sep. 14th , 9:30 a.m

    Where:

    Room 517, Office Block, 2 West Beijing Road (PMO, CAS)
     
     

    Welcome to Attend

     
      ( PMO Academic Committee & Academic Circulating committee)
     
     

     

    Abstract  
    The magnetic energy and helicity in emerging active regions are calculated using the HMI vector magnetic field data and DAVE4 VM (Schuck 2008) technique. The active regions studied in the paper, from simple to complicated, are AR11072, AR11117 and AR11158. It is found that (1) in two active regions the sign of the helicity is against the hemisphere rule; (2) the helicity in the corona are predominantly contributed by the surface flows; (3) comparing with the emergence of magnetic flux, the helicity flux through the photosphere shows a slight delay in phase; (4) the energy and helicity fluxes due to surface flows are significant during emergence of magnetic flux, and become much smaller after the emergence stops, while the energy flux from the vertical flow is still significant. A discussion is also placed here.

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