Magnetic fields in the photosphere and heliosphere: structure, statistical parameters, turbulent...
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Transcript of Magnetic fields in the photosphere and heliosphere: structure, statistical parameters, turbulent...
Magnetic fields in the photosphere and heliosphere:
structure, statistical parameters, turbulent state
Valentyna I. AbramenkoBig Bear Solar Observatory of NJIT
Email: [email protected]
http://www.bbso.njit.edu/~avi/
Outlook
• Analysis of line-of-sight magnetograms: - Magnetic energy dissipation structures - Magnetic power spectrum: flare productivity forecast
• Analysis of the parameters of coronal holes: - Dipole emergence rate in coronal holes - Magnetic Power Spectrum: expansion into the heliosphere
• Distributions of the magnetic field discontinuities in the solar wind ACE data
Magnetic energy dissipation structuresAbramenko, Yurchyshyn, Wang H., Spirock, Goode 2003, ApJ 597
Coronal Heating
High magnetic energy dissipation rate in the photosphere is associated with high temperature and emission measure in
the corona.
Abramenko, Pevtsov, Romano 2006 ApJ 646
Magnetic Power Spectrum:
Flare-quiet active region 0061 Flaring active region 9077
PS(corrected) = PS(Full Disk) / Correction Function
Correction Function = PS (Full Disk) / PS (High Res)
Emerging Active Region 0488
The power index peaked by the end of the first day of AR’s life, while
the magnetic flux has saturated by the end of the 3rd day
flare flare contaminatedcontaminatedmeasurementsmeasurements15h15h
Soft X-ray Flare Index
versus Magnetic power index Abramenko 2005, ApJ, 629
Further study of photosphericmagnetograms
• Separate study of emerging ARs• Power spectrum from magnetograms
obtained with SDO and Solar B (possibility for extension of the inertial range, for study of the dissipation range?)
• Power spectra from different areas on the Sun (ARs, plage areas, Quiet Sun areas, CHs)
• Structure Functions and Filling Factor in different areas on the Sun
Collaborations in frameworks of theHeliospheric Focus Team
• Study of the magnetic field parameters inside coronal holes (collaboration with L.A.Fisk and T. Zurbuchen)
• Analysis of the statistical parameters of the
solar wind data (collaboration with B.Vasquez and D.Haggerty)
The Rate of Emergence of Magnetic Dipoles in Coronal Holes and Outside
In all cases, the dipole emerging rate for CHs is lower than that for adjacent QS areas (all data points are above the bisector).This implies that a coronal hole is a region with a local minimum in the rate of emerging dipoles
• This result supports the concept that reconnection of open field lines with coronal loops is an important transport mechanism on the Sun (Fisk 2005), and needs to be included in models for the evolution of the solar magnetic
field.
The dipole emergence rate in Quiet-Sun areas exceeds approximately twice that in Coronal Holes.
This implies that a coronal hole is a region with a local
minimum in the rate of emerging dipoles.