2.1 Chorus measurements
Chorus wave measurements were obtained from the Van Allen Probes (RBSP A, B), Arase, and ground-based VLF data from the Canadian Space Agency’s Geospace Observatory Array for Broadband Observations of VLF/ELF Emissions (GO-ABOVE) receivers [Cully et al. , 2014], PWING (study of dynamical variation of Particles and Waves in the INner magnetosphere using Ground-based network observations) and Sodankyla networks [Shiokawa et al. , 2017]. RBSP had a near-equatorial elliptical orbit ranging from ~600 km to >6\(R_{E}\) apogee. Due to the 11 magnetic inclination, magnetic latitudes of up to 20° and L values of up to L>6 were sampled. The Arase satellite has an elliptical orbit, with apogee at 32,000 km, perigee at 400 km, and inclination of 31° magnetic latitude [Miyoshi et al. , 2018a].
Wave data were provided by the RBSP Electric Field and Waves (EFW) [Wygant et al. , 2013] and the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) [Kletzing et al. , 2013] instruments, and energetic electron data were provided by the Magnetic Electron Ion Spectrometer (MagEIS) [Blake et al. , 2013]. Chorus waves on Arase are identified from one second resolution spectra from Arase’s Onboard Frequency Analyzer (OFA); part of the Plasma Wave Experiment (PWE) instrument suite [Kasaba et al.,2017; Matsuda et al. , 2018; Kasahara et al. , 2018;Ozaki et al. , 2018b]. Energetic electron data was obtained by the High-energy electron experiments (HEP) [Mitani et al. , 2018] onboard Arase.
2.2 Microburst measurements
Electron microburst measurements were obtained from FIREBIRD II and AC6-A CubeSats. FIREBIRD II was launched in 2015 into an orbit of 632 km by 433 km at 99.1 inclination. The twin FIREBIRD CubeSats, Flight Units 3 and 4 (FU 3 and FU 4 hereafter), detect energetic electrons from ~250 – 1000 keV in five differential energy channels and one integral (>1 MeV) channel [Spence et al. , 2012; Klumpar et al. , 2015; Crew et al. , 2016]. For microburst observations on FIREBIRD, we use high resolution data (50 msec sampling) from the lowest differential energy channel of each collimated detector (230 – 300 keV on FU3 and 219 – 283 keV on FU4;Johnson et al., 2020). Microbursts are often observed also in the higher energy channels but generally at decreased fluxes. AC6-A was launched in 2014 into a low Earth orbit of 620 km by 700 km at 98 inclination, carrying a suite of three radiation dosimeters. The current study uses the >35 keV dosimeter for electrons, which operates in a 10 Hz mode to resolve microbursts. To identify microbursts on both FIREBIRD and AC6-A we combined an automated detection method [O’Brien et al. , 2003; Shumko et al. , 2020] with a visual verification.