Catalogs of Quasi-Periodic X-ray (QPX) variations at Balloon Array for Radiation belt Relativistic Electron Losses (BARREL)

The Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) mission was designed to study the loss of radiation belt electrons to the upper atmosphere. Particle precipitation is inferred by measurements of Bremsstrahlung X-rays generated from the interaction of electrons with the Earth’s atmosphere (Millan et al., 2013; Woodger et al., 2015). The catalogs are based on reduction of the BARREL calibrated Slow Spectrum (SSPC) dataset to a time series by integrating the X-ray counts over the energy bins from ≈50 keV to ≈178 keV and summed the counts over three time steps and converted the measurements to counts per second with a cadence of 96 s. We identified four classes of events: intervals with Quasi-Periodic X-ray (QPX) variations; intervals in which both X-ray counts and time shifted solar wind density show quasi-periodic variations (QPX+PDS events) with frequency difference less than ≈0.28 mHz and time difference less than 30 min; intervals that overlap with time periods of enhanced precipitation respectively defining the QPX+Precip. and QPX+PDS+Precip. classes. The list of time periods with enhanced precipitation is available at https://barreldata.ucsc.edu/data_products/v10/TotalEvent_file_2013_2016v5.txt. Each catalog contains: start and end time covered by the power spectrum enhancement marking the QPX variations; the balloon name, the frequency and amplitude of the QPX variation, the median altitude of the balloon during that interval, the L-shell (McIlwain Lm parameter) and Magnetic Local Time (MLT) at the center time of the interval, flag indicating the presence (1) or not (0) of a similar periodicity in the altitude time series. Additionally, we provide catalogs obatained by time series by avoiding the time binning and using 32s cadence time series obtained by linear interpolation (the SSPC dataset has very small variations in the sampling time that keep it close but not exactly at 32s). We also include figures analogous to the ones in the corresponding manuscript (see below) but based on these catalogs. A complete description of the methodology and criteria used to identify the events is available at: Di Matteo, S., Breneman, A., Halford, A., Viall, N., Kepko, L., Cantwell, K., and Millan, R. (2026) Quasi-Periodic X-ray Variations at BARREL: Role of Electron Precipitation and Solar Wind Driving. Journal of Geophysical Research: Space Physics