Wavelet Analysis of Solar Flare Hard X‐Rays

We apply a multiresolution analysis to hard X-ray (HXR) time proles f (t) of solar ares. This method is based on a wavelet transform (with triangle-shaped wavelets), which yields a dynamic decomposition of the power at di erent timescales T , the scalogram P(T , t). For stationary processes, time-averaged power coefficients, the scalegram S(T ), can be calculated. We develop an algorithm to transform these (multiresolution) scalegrams S(T ) into a standard distribution function of physical timescales, N(T ). We analyze 647 solar ares observed with the Compton Gamma Ray Observatory (CGRO), recorded at energies 25 keV with a time resolution of 64 ms over 4 minutes in each are.