1. SOLAR FLARE OPTICAL SPECTROPOLARIMETRY
Zhi XU (1,2), Jean-Claude HENOUX (1), Gilbert CHAMBE (1), Alexander PETRESHEN (3) and Cheng FANG (4)
(1) OBSERVATOIRE DE PARIS, LESIA, France
(2) YUNNAN OBSERVATORY, China
(3) St PETERSBURG INSTITUTE OF OPTICS, Russia
(4) NANJING UNIVERSITY, China
Xu et al , ApJ, 631, 618
Xu et al , ApJ submitted
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2. THEMIS OBSERVATIONS June 15th 2001 Flare Hard X-rays X 65° HXRS
29 – 44 keV
44 – 67 keV
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3. 2D distributions of Ha (left) and Hb (right) polarization (at 10:07 UT), and of the longitudinal magnetic field B//.
P radial
P tangential
P radial
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4. 2D distribution of Ha, Hb and Mg I 552.84 nm
line linear polarization at 10:07 UT
Polarization:
Radial: triangles
Tangential: stars
Ha (blue)
Hb (green)
Mg I (red)
Line-center intensity
contours
Ha (dotted line)
MgI (solid line)
0.42 arc second square/pixel
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5. Time variation of Mg I line impact polarization
10 pixels averaged
intensity (triangles)
- polarization degree (stars)
from 10:07 to 10:12 UT.
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6. CONCLUSIONS The Ha, Hb and Mg lines are linearly polarized.
The highest polarization is observed at flare kernels borders.
Radial linear polarization is present in Ha, Hb and Mg lines.
Tangential linear polarization in Ha is also present .
Both return current electrons associated with electron beams and low energy protons can explain the readial polarization observed.
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