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: avi@bbso.njit.edu

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.