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Chromospheric Magnetic Field Measurements in a Flare and an Active Region Filament View all abstracts by submitter

John Harvey   Submitted: 2012-03-08 14:41

Intensity (I) and circular polarization (V) spectra using the 854 nm line of Ca II with 3.65 pm spectral and 1 arcsecond spatial sampling were obtained with the SOLIS vector spectromagnetograph on 2011 November 8. An active region filament showing Doppler shifts as large as 50 km s-1 and an unrelated C1.8 flare were observed. Line-of-sight flux density estimates of the magnetic field (Blos) were mapped as a function of wavelength in both of these features using the weak-field Zeeman-splitting approximation that V is proportional to the first derivative of I. The filament had a large amount of structure in intensity and velocity but remarkably little Blos structure, which varied smoothly from 35 to 55 G. Two flare emission kernels showed average Blos values of 415 and -215 G, about 85% of the underlying photospheric fields. Counter to this modest strength decrease with increasing height, in nearly all parts of the brighter flare kernel there appears to be a substantial increase of Blos at the height corresponding to the central core of the 854 nm line. This increase, if verified, may be related to compression of the chromosphere associated with chromospheric evaporation. Alternatively, it might indicate that the profile of the line core is narrowed in the magnetic part of the flare kernel. The results presented here are generally similar to previous, rather sparse observations. Observations of the type reported here are made daily and could be used to greatly increase knowledge about the chromospheric magnetic field in active solar features.

Authors: Harvey, J.W.
Projects: None

Publication Status: Solar Physics (submitted)
Last Modified: 2012-03-09 21:05
Go to main E-Print page  The Occurrence and Speed of CMEs Related to Two Characteristic Evolution Patterns of Helicity Injection in Their Solar Source Regions  The non-Maxwellian continuum in the X-ray, UV, and radio range  Edit Entry  Download Preprint  Delete Entry 

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