Data Analysis and Basic Observational Results

Abstract

Matthaeus and Goldstein (1982a, b, 1983) and Matthaeus et al. (1986) established that the interplanetary magnetic field often behaves as a stationary and ergodic random function of time. At least it can be meaningfully viewed as a’weakly’ stationary random function (i.e., the stationarity of the average and the two-pointtime correlation function is ensured). The time averages of the products of turbulent fields at fixed points in space are equivalent in practice to ensemble averaging. These averages are then insensitive to the origin in time locally. In that case, the mean of a time series B(t) is $${B_0} = \left\langle {B(t)} \right\rangle $$ (2.1) where ‘B0’ is independent of time. The two point correlation function is defined by $$R(\tau ) = \left\langle {\delta B(t)\delta B(t + \tau )} \right\rangle $$ (2.2) Where δB=B-B0