DRAFT: A Method for Wave Analyses in Space Plasmas

Abstract In this study, we apply a method for wave analyses in space plasmas, to better understand the nature of plasma waves and turbulence. Such is based on four-spacecraft measurements magnetic fields or electric fields; it calculates phase velocity each single-frequency by using timing analysis, then divides frequency obtain wavevector, finally solves dispersion relation ( ? – k relation) considering all channels, thus termed Dispersion RelAtion From Timing (DRAFT). Quantitatively, define three parameters, match amplitude (MOA), ratio half-wavelength spacecraft separation ?/ 2 R sc ), correlation coefficient (CC), judge reliability method. We illustrate usage validate efficiency parameters analyzing Magnetospheric Multiscale data. find that DRAFT results are generally accurate under conditions MOA > 0.5, ? /2 1, CC 0.8. As support, compare our with previous methods such as Means singular value decomposition (SVD). if criteria (MOA, , CC) satisfied, DRAFT, Means, SVD consistent resolving normal angle. comparison robustly validates rationality Using successfully solve an Alfvén Earth’s magnetosheath its three-dimensional K -spectrum. Our should be useful study low-frequency weak turbulence plasmas.