THEMIS ULF power dataset

This dataset is for magnetic field wave power in the Ultra Low Frequency range for the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites A, D, and E. Version 1.0 of the dataset is uploaded here. Please see a related JGR-Space Physics publication (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023JA031987) for further information and examples using the dataset.

The wave power measurements are provided in mean Field-aligned coordinates where z is along the magnetic field direction, x=PhiSM x z where PhiSM is the azimuthal direction in SM coordinates, and y completes the right-hand orthogonal set.

All data are contained in a .mat file generated in MATLAB R2022a, “THEMIS_ULF_database.mat”. The file contains the following variables:frequencies1024 – Frequencies in HzthaTime – Start and stop time of each THEMIS-A satellite DFT window in Matlab time format (use datestr to get time string).thaSMpos – Average x, y, and z position in Cartesian SM coordinates of the THEMIS-A satellite during each DFT window, units of Earth radii.tha_BMFA_PSDx – The x component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-A spacecraft.tha_BMFA_PSDy – The y component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-A spacecraft.tha_BMFA_PSDz – The z component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-A spacecraft.thdTime – Start and stop time of each THEMIS-D satellite DFT window in Matlab time format (use datestr to get time string).thdSMpos – Average x, y, and z position in Cartesian SM coordinates of the THEMIS-D satellite during each DFT window, units of Earth radii.thd_BMFA_PSDx – The x component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-D spacecraft.thd_BMFA_PSDy – The y component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-D spacecraft.thd_BMFA_PSDz – The z component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-D spacecraft.theTime – Start and stop time of each THEMIS-E satellite DFT window in Matlab time format (use datestr to get time string).theSMpos – Average x, y, and z position in Cartesian SM coordinates of the THEMIS-E satellite during each DFT window, units of Earth radii.the_BMFA_PSDx – The x component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-E spacecraft.the_BMFA_PSDy – The y component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-E spacecraft.the_BMFA_PSDz – The z component (mean field-aligned coordinates) of wave power as a function of frequency and time in units of nT^2/Hz for the THEMIS-E spacecraft.