Fig. 4
From: Continuous Doppler sounding of the ionosphere during solar flares
a Ionizing fluxes recorded by GOES-15 satellite on 22 October 2014 from 13:45 to 14:55 UT. X-ray fluxes in the ranges 0.1–0.8 nm and 0.05–0.4 nm by red and blue, respectively. EUV H-lyman-alpha flux and EUV flux in the range 25–35 nm by magenta and orange, respectively. b Time derivatives of the X-ray fluxes, dFX/dt, (red for 0.1–0.8 nm, blue for 0.05–0.4 nm) and 0.1 × dFEUV/dt of the EUV H-lyman-alpha flux (magenta) and of the 25–35 nm channel (orange). c Observed Doppler shift at f = 7.04, 4.65 and 3.59 MHz by black, red, and blue, respectively. d Virtual plasma velocity u *P obtained by Eq. (3) for f = 7.04, 4.65 and 3.59 MHz by black, red, and blue, respectively