On the periodicity of high speed solar wind streams

Abstract

In the paper we have investigated the periodicity of high speed solar wind (HSSW) streams using the technique of power spectrum analysis. The data for HSSW streams has been taken from the papers by Lindblad and Lundstedt (1981, 1983) and Lindblad et al. (1989) The power spectrum analysis of the daily HSSW streams events for the period 1964 – 1975 (solar cycle 20) shows peaks of 14, 7, 2.9 and 2.6 days, and daily HSSW events for the period 1976 – 1982 (solar cycle 21) shows peaks of 15.4, 7, 2.9 and 2.6 days. The HSSW events for period 1964 – 1982 (solar cycles 20-21) shows peaks of 15.4, 7 , 3.7, 2.9 and 2.6 days. The common periods from above study are 7, 2.9 and 2.6 days. The 2.9, 2.6 days and other periods are folding frequency. The 7 days periodicity is close to the 1/4 th of solar rotation which may be the time for energy build up for coronal holes to produce HSSW streams