Title:
Temporal Dependences Between Impulsive Emission of the H-alpha Flaring
Kernels and Variations of the Soft and Ha
rd X-ray Fluxes.

Authors:
K. Radziszewski  and  P. Rudawy

Institute:
Astronomical Institute of University of Wroclaw
ul. Kopernika 11, 51-622 Wroclaw, Poland

Abstract.
During impulsive phase of the solar flares numerous pulses of the X-ray
emission are emitted as a result of hitt
ing the dense chromosphere by beams of the high-energy particles
(bremsstrachlung). The high cadence observation
s made in selected spectral lines of the visual domain (especially in
H-alpha) reveal also short living pulses o
f the emission, well correlated in time with the pulses of the hard X-ray
(HXR) flux.
For many flares a derivative of the soft X-ray (SXR) flux shows very good
correlation in time with variations of
 the HXR (Neupert effect). We present here an analysis of the temporal
dependences between impulsive emission of
 the H-alpha flaring kernels, observed with very high temporal resolution
(40-75 ms) and variations of the SXR e
mission, using the Neupert effect (calculated for SXR GOES and RHESSI
observations).
The analyzed H-alpha data were collected with the Multi-Channel Subtractive
Double Pass (MSDP) spectrograph and
Solar Eclipse Coronal Imaging System (SECIS) in Bialkow Observatory
(University of Wroclaw, Poland). We evaluate
d six flares observed on July 16, 2003, May 21, 2004, July 12, 2005 (3
events) and July 13, 2005, obtaining the
H-alpha light curves in numerous freely-chosen wavelengths in range +/- 1.2
Angstrem from line centre.  We have
found high temporal conformity between impulsive changes of the H-alpha and
X-rays. The individual pulses observ
ed in visible domain were delayed by a few or more seconds in respect to
moments of the energy releases pointed
by the impulses of the HXR or local maxims of the derivative of the SXR.