E-Print Archive

There are 3914 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
The scalings of the coronal plasma parameters with the mean photospheric magnetic field: The long-term evolution of AR 7978 View all abstracts by submitter

Pascal Demoulin   Submitted: 2002-12-05 08:20

We analyze the evolution of the fluxes observed in X-rays and correlate them with the magnetic flux density in active region NOAA 7978 from its birth throughout its decay, for five solar rotations. We use SoHO/MDI data to derive magnetic observables, together with Yohkoh/SXT and Yohkoh/BCS data to determine the global evolution of the temperature and the emission measure of the coronal plasma at times when no significant brightenings were observed. We show that the mean X-ray flux and derived parameters, temperature and emission measure (together with other quantities deduced from them, such as the density and the pressure), of the plasma in the AR follow power-law relationships with the mean magnetic flux density (ar{B}). The exponents (b) of these power-law functions (a ar{B}b) are derived using two different statistical methods, a classical least-squares method in log-log plots and a non-parametric method, which takes into account the fact that errors in the data may not be normally distributed. Both methods give similar exponents, within error bars, for the mean temperature and for both instruments (SXT and BCS); in particular, b stays in the range [0.27,0.31] and [0.24,0.55] for full resolution SXT images and BCS data, respectively. For the emission measure the exponent b lies in the range [0.85,1.35] and [0.45,1.96] for SXT and BCS, respectively. The determination of such power-law relations, when combined with the results from coronal heating models, can provide us with powerful tools for determining the mechanism responsible for the existence of the high temperature corona.

Authors: van Driel-Gesztelyi L., Demoulin, P., Mandrini C.H., Harra, L., Klimchuk, J.A.
Projects:

Publication Status: ApJ, preprint, in press
Last Modified: 2002-12-05 08:20
Go to main E-Print page  Astrophysics 2002 (Section 2: Solar Physics)  Testing coronal heating models: The long-term evolution of AR 7978  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Key
Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Linear Polarization Features in the Quiet-Sun Photosphere: Structure and Dynamics
Solar Microflares Observed by SphinX and RHESSI
Two Kinds of Dynamic Behavior in a Quiescent Prominence Observed by the NVST
Resistively-limited current sheet implosions in planar anti-parallel (1D) and null-point containing (2D) magnetic field geometries
Is It Small-scale Weak Magnetic Activity That Effectively Heats the Upper Solar Atmosphere?
Self-Similar Approach for Rotating Magnetohydrodynamic Solar and Astrophysical Structures
Spectroscopic and imaging observations of small-scale reconnection events
A Study of Magnetic Field Characteristics of Flaring Active Region Based on Nonlinear Force-free Field Extrapolation
A Study of a Compound Solar Eruption with Two Consecutive Erupting Magnetic Structures
Non-potential magnetic helicity ratios at the onset of eruptions
Solar Cycle Observations of the Neon Abundance in the Sun-as-a-star
Subresolution Activity in Solar and Stellar Coronae from Magnetic Field Line Tangling
A Model of Zebra Patterns in Solar Radio Emission
Three-dimensional magnetic reconnection in a collapsing coronal loop system
On the Synthesis of GOES Light Curves from Numerical Models
Efficient Calculation of Non-Local Thermodynamic Equilibrium Effects in Multithreaded Hydrodynamic Simulations of Solar Flares
2D solar wind speeds from 6 to 26 solar radii in solar cycle 24 by using Fourier filtering
Non-damping oscillations at flaring loops
An Event-Based Verification Scheme for the Real-Time Flare Detection System at Kanzelhöhe Observatory
Computation of Relative Magnetic Helicity in Spherical Coordinates

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey



© 2003 Solar Physics Group - Montana State University