Fig. 7
From: Role of hard X-ray emission in ionospheric D-layer disturbances during solar flares
Photon flux (in photons/s/cm\(^2\)) of the flares considered in Fig. 6, for two times: the peak of the HXR (top) and the peak of SXR (bottom). The final black spectrum results from the composition of several fits for the thermal part and non-thermal parts. The model of each fit is described on the bottom left together with the colour code (red, green and yellow). The purple curve indicates the background level. The time interval to build the photon flux is indicated on the upper part of each panel. The vertical dashed line on the left panel indicates the energy limit of the fit