NASA Goddard Space Flight Center, Laboratory for Extraterrestrial Physics, Greenbelt, Maryland 20771

A new dynamic periodogram technique has been developed to study variations in the solar wind plasma and magnetic field parameters collected primarily by IMP-8 during its more than twenty years of mission life. The long data set and the new technique allows the determination of changes in the various periodicities as a function of time. For example, a 1-year oscillation is shown to be most pronounced during solar minima, while during solar maxima half-year and 2-year periodicities are dominant. Many other periodicities (~36, 50, 73, ~154 days, ~9 months, and 1.3-years) are identified and their time dependencies investigated.

in Solar Wind Eight, Proc. of the Eighth Intern. Solar Wind Conf., Dana Point, Ca, June 1995, D. Winterhalter ed., Amer. Inst. of Physics, Woodbury, New York