Diagnostic of Chromospheric Flare Plasma Debi Prasad Choudhary California State University Vasyl Yurchyshyn Big Bear Solar Observatory

Solar Flare Sites

Chromospehric Magnetograms

Optical Spectra Instruments like: Solar Chromospheric Flare Spectrograh and Interface Region Imaging Spectrograh

STOKES profile dignostics Example of a Stokes-V profile. Vmax-P, Vmin-P and Vmax-n, Vmin-n are the maximum and minimum signal of Stokes-V profiles with longitudinal magnetic field of opposite polarity. λ0,and λ0are the zero crossing wavelengths of Stokes-V profiles from magnetic field of opposite direction. λ0 the relative Doppler shift of magnetic elements.

Stokes I, Q, U, V spectra observed at a slit position that include the light bridge of the sunspot observed in photospheric line Fe 6300 A. The high speed locations at the slit locations of 155 arc second can be noticed in both the spectra, especially in Stokes-V profiles where white shade is extended in the red wavelengths.

The lines profiles of Stokes I spectra at the location of the high speed down flow near the light bridge of the sunspot observed in chromospheric Mgb2 5172 A lines. The solid line is observed line profile in quiet sun locations which is superimposed with the dashed line that is generated by convolving the instrumental profile with the KPNO atlas solar profile. The broad dotted and dashed profiles are from different parts of the down-flow locations.

The Stokes spectra and profiles in Ca II λ854. 2 nm line The Stokes spectra and profiles in Ca II λ854.2 nm line. (left) Top: Image of the sun with the horizontal dark line representing the slit position passing over the sunspot. Next four strips are the images of the spectra in Stokes I, Q, U and V in photospheric Fe I 630.2 nm line. The bottom two images represent the Stokes I and V spectra in chromospheric Ca II 854.2 nm line. (right) Stokes I and V line tracings of sunspot region. These observations are the example of the data obtained with SOLIS VSM.

The Session Describe the new tools that are now available. Identify the features of solar flares that can be addressed by using the modern tools. Formation of a group to focus the flare and CME research using these tools.

Line bisectors of Stokes-I profiles Line bisectors of Stokes-I profiles. The + symbol is for the line profiles in the quiet sun. The other symbols are for the line profiles in the high speed down-flow locations. The maximum speed is ~ 23.4 km s-1. The four figures are from different patches of high speed flow locations.

The main results of these observations are: (a) the compact discrete high speed down-flow locations were situated on both sides of magnetic field reversal line, (b) these locations are long lived that requires sustained mass flow. The localized downflows regions were observed in both polarities across the neutral line, but no up flow locations were seen. The only mechanism that provides sustained flows are the ones related to Evershed flows. The observed down-flow locations in the photosphere could be foot-points of the sigmoidal. Our observations also suggest that there are strong organized plasma flows inside sigmoidal coronal magnetic loops.