Methodology:

The data used in this study come from the NASA Van Allen Probe A. The wave data used in this study were downloaded from https://emfisis.physics.uiowa.edu/data/index and the magnetic ephemeris data were downloaded from https://www.rbsp-ect.lanl.gov/data_pub/rbspa/MagEphem/. The AE indices used in this study were downloaded from the NSSDC Omniweb. Full details of the subsequent analysis are given in Meredith et al. [2019].

Data collection:

We use data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on board Van Allen Probe A. The wave electric field of the VLF transmitter signals is measured using the wave High Frequency Receiver (HFR). This instrument provides measurements of one component of the wave electric field in the plane perpendicular to the spin axis in 82 logarithmically spaced frequency bins in the frequency range 10 to 487 kHz every 6 s. For comparison with published wave magnetic field intensities and for use in diffusion calculations we also convert the wave electric field to the wave magnetic field. This requires knowledge of the electron gyrofrequency and the electron plasma frequency. The former is determined directly from the 1s fluxgate magnetometer measurements of the local magnetic field. The electron plasma frequency is derived from the HFR data and provided as a Level 4 data product. The data were subsequently analysed and processed as described in Meredith et al. [2019].

Data quality:

The wave data have been calibrated and quality-controlled prior to release.