%0 Journal Article %T Resolving different sources of fast X-ray variability of the dwarf nova RU Peg in quiescence %A A. Dobrotka %A S. Mineshige %A J. -U. Ness %J Physics %D 2013 %I arXiv %R 10.1093/mnras/stt2311 %X We analysed an X-ray light curve of the dwarf nova RU Peg taken by XMM-Newton with a duration of 46300 s. The power density spectrum has a complicated shape with two red noise and two white noise components, indicating the presence of two turbulent regions. We developed a statistical "toy model" to study light curves with variability produced by an unstable turbulent accretion flow from the inner disc. Our results are consistent with a disc truncation radius maximally 0.8 x 10^9 cm. We found that any fluctuation of the viscous mass accretion at the inner disc are visible as UV and X-ray variations with the same break frequency in the power density spectrum. This process is generating low frequency variability. A second break suggests the presence of a faster X-ray variability component which must be generated by another process likely localised between the inner disc and the white dwarf. %U http://arxiv.org/abs/1311.7487v1