The gradient of the small-scale velocity fluctuation in the solar atmosphere

The vertical small-scale velocity gradient in the photosphere is determined using spectrograms of high spatial resolution obtained with the Gregory-Coude telescope in Izana on August 1, 1986. The measured Doppler shifts along the spectrograph slits are analyzed using spatial Fourier analysis. The height dependence of the size of the velocity fluctuations measured at Doppler velocity is examined. It is observed that both the amplitude of the smallest velocity structures and the integrated rms small-scale velocity decrease with height in the photosphere. The derived rms small-scale velocity values are compared with the data of Canfield (1976) and Nesis (1985), and good correlation is observed.