Abstract:
The active region NOAA (National Oceanic and Atmospheric Administration) AR 10486
which appeared on the solar disc in 2003 October produced a lot of space weather related
activity. Here, we report on the co-spatial evolution of the photospheric Doppler enhancements
and the chromospheric Hα flare ribbons observed during the 4B/X17.2 class solar flare of 2003
October 28 in this active region. These velocity enhancements exactly match the Hα brightness
enhancements in space, and are delayed by approximately 1 min in time. Hα brightness attains
a maximum nearly at the same time as the peak seen in light curves in high-energy emission
observed by KORONAS (Kuznetsov et al. 2006).
