View
56
Download
0
Category
Tags:
Preview:
DESCRIPTION
RHESSI/SOHO/TRACE Workshop. Pre-event Physics. December 8-11, 2004,Sonoma, California. Diagnostics of flare activity level from turbulence parameters of photospheric plasma. Abramenko, Valentyna Big Bear Solar Observatory of NJIT avi@bbso.njit.edu www.bbso.njit.edu/~avi. Introduction. - PowerPoint PPT Presentation
Citation preview
Diagnostics of flare activity level from turbulence parameters of
photospheric plasmaAbramenko, Valentyna
Big Bear Solar Observatory of NJITavi@bbso.njit.edu
www.bbso.njit.edu/~avi
RHESSI/SOHO/TRACE WorkshopPre-event Physics
December 8-11, 2004,Sonoma, California
Introduction
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
A solar flare may be triggered as a chain reaction in a stressed coronal magnetic configuration.
Flares occur as an unavoidable phase in evolution of a complex non-linear dynamical system of magnetized plasma (Parker 1988, a review by Charbonneau et al. 2001)
The system extents from the convective zone to the corona through layers of plasma of different physical conditions.
Introduction
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Introduction
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Essential properties of the photospheric plasma:
Magnetized plasma in a turbulent state (Parker 1979),
very intermittent (or, in other words, multifractal) medium (Lawrence et al. 1993, Abramenko et al. 2002),
where the magnetic helicity may have an inverse cascade (Biskamp 1993)
Introduction
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Situation in the photosphere – flaring in the corona:
Magnetic helicity transport in the photosphere (Rust & LaBonte 2003; Georgoulis, Rust & LaBonte – present meeting; Chae 2001; Romano – present meeting ).
Statistical properties of electric currents, current helecity, magnetic flux, etc., derived from vector-magnetograms (Leka & Barnes 2004).
Introduction
Fractal dimensions of the photospheric magnetic fields (Tarbell et al. 1990; Balke et al. 1993; Meunier 1999;
Ireland, Gallagher & McAteer 2003).
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Situation in the photosphere – flaring in the corona: we propose to analyze
3. Multifractality (intermittency) of the photospheric magnetic fields – poster at the current meeting. (Abramenko, Yurchyshyn, Wang, Goode, ApJ 577, 2002).
2. Turbulence state of the photospheric magnetic field as derived from magnetic power spectrum – present talk.
Introduction
1. Distribution functions of the magnetic flux in elements of the magnetic field in active regions – present talk. (Abramenko & Longcope, ApJ, 2005)
Distribution functions of the magnetic flux
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Flare-quiet active region 0061 (C2) Flaring active region 9077 (X5.7)
(Abramenko & Longcope, ApJ, 2005)
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Distribution functions of the magnetic flux(Abramenko & Longcope, ApJ, 2005)
Magnetic Power Spectrum:
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Flare-quiet active region 0061 Flaring active region 9077
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Flare-quiet active region 0061
Flaring active region 9077 Magnetic Power Spectrum:
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Flare-quiet emerging active region NOAA 9851
No X-ray flares during the passage across the disk
Magnetic Power Spectrum:
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Flaring emerging active region NOAA 0365
The most powerful flare during the passage across the disk: X3.6
Magnetic Power Spectrum:
Multifractality vs. Turbulence
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
9773/M9.5
9866/M5.7
9077/X5.7
0515/ -
0306/C19851/ -
0061/C2
Jul 13Jul 14
Flaring ARs
Flare-Quiet ARs
Classical Kolmogorov Turbulence state
Conclusions
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
1. Parameters of the turbulence state (the power index ) and of the structural organization (the distribution
functions and the degree of multifractality, h) of the photospheric magnetic field correlate with flaring productivity of an active region.
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
2. The turbulence state of the magnetic field at the phase of emergence seems to determine the ongoing flare productivity of an active region.
3. Further study on a large statistics is needed: the catalog of active regions observed in a high resolution mode by SOHO/MDI will be used
(Paolo Romano & Vasyl Yurchyshyn, www.bbso.njit.edu/~vayur/MDI_catalog.htm)
Conclusions
Calculation of Multifractality
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Structure functions were first introduced by Kolmogorov (1941). They were defined as statistical moments of the field increments:
Classical Kolmogorov theory
Refined Kolmogorov theory, multifractal structure
q is the order of a statistical moment, r is a separation vector, x is the current point on a magnetogram. <…> denotes the averaging over a magnetogram. q is a slope within the inertial range of scales.
Calculation of Multifractality
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Historically accepted terminology:Historically accepted terminology:Analysis of Time series : intermittencyAnalysis of Spatial arrays : multifractality
h(q)= d(q)/dq D(h(q))=2+qh(q)- (q)
Examples of different multifractality
Calculation the Power Spectrum
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Calculation the Power Spectrum
RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California
Recommended