Whistler-mode chorus waves play a key role in driving radiation belt dynamics by enabling both acceleration of electrons to relativistic energies as well as their loss into the atmosphere via pitch-angle scattering. The ratio between the electron plasma frequency (fpe) and the electron gyrofrequency (fce) significantly influences the efficiency of these processes, with electron acceleration being most effective during periods of low fpe/fce. In this study, a combined total of approximately 24.5 years of THEMIS wave data are analyzed to show how chorus wave intensity and spatial location vary with relative frequency, geomagnetic activity and fpe/fce. Results demonstrate that the strongest chorus emissions are observed during active conditions. At these times, equatorial chorus at low relative frequencies (flhr<f<0.1fce) is strongest when fpe/fce is high (fpe/fce>10) primarily in the region 5<L*<8, from 22:00-12:00 MLT. In sharp contrast at high relative frequencies (0.5fce<f<0.7fce), the equatorial chorus is strongest when fpe/fce is low (fpefce<6) mainly in the region 4<L*<6 from 21:00-09:00 MLT. At intermediate relative frequencies (0.3fce<f<0.4fce), equatorial chorus is strongest in the region 3.5<L*<8 from 21:00-12:00 MLT. In the off-equatorial region the strongest waves are seen in the frequency range (0.1fce<f<0.3fce) between 5<L*<8 and 06:00-15:00 MLT and again are mostly independent of fpe/fce. We show that the location of the strongest waves can be largely explained in terms of the source electrons being in the required energy range for resonance and the absence of Landau damping and highlight the regions where electron acceleration to relativistic energies is likely to be mostly significant.

Relativistic electrons are an important space weather hazard, being a major source of radiation damage to satellites and posing a risk to humans in space. We use approximately 20 years of data from the US Global Positioning System (GPS) satellite NS41 to determine the characteristics of the geomagnetic storms that lead to the largest relativistic electron fluxes in GPS orbit. The largest CME-driven events are associated with the solar wind having negative excursions of the IMF Bz with minimum values of ~-14 nT two hours prior to zero epoch, defined as the time of the minimum in the Dst index and strong Dst minima, reaching ~-130 nT at zero epoch. In contrast, events driven by high speed solar wind streams (HSSs) are associated with smaller negative excursions of IMF Bz with minimum values of ~-4 nT two hours prior to zero epoch and moderate Dst minima, reaching ~-60 nT at zero epoch. Compared with HSS-driven events, peak E = 2.0 MeV fluxes associated with CME-driven events are larger by factors of 1.3 at L=4.5 and 2.4 at L=6.5. Both the CME- and HSS-driven events are associated with enhancements in the solar wind number density and pressure prior to zero epoch. Following zero epoch the solar wind number density and pressure become low and substorm activity is enhanced for several days.

Whistler mode chorus is an important magnetospheric emission, playing fundamental roles in the dynamics of the Earth's outer radiation belt and the production of the Earth's diffuse and pulsating aurora. In this study we extend our existing database of whistler mode chorus by including ~3 years of data from RBSP-A and RBSP-B and an additional ~6 years of data from THEMIS A, D, and E, greatly improving the statistics and coverage in the near-equatorial region (|MLAT|<18^o). We produce new global maps of whistler mode chorus as a function of spatial location and frequency. This work is reported in Meredith et al. [2020] and the data provided here enable reconstruction of all of the figures in the paper. The research leading to these results has received funding from the Natural Environment Research Council (NERC) Highlight Topic grant NE/P01738X/1 (Rad-Sat) and the NERC grant NE/R016038/1. Wen Li and Xiao-Chen Shen received funding from NASA grants NNX17AG07G and 80NSSC19K0845, NSF grant AGS-1847818, and the Alfred P. Sloan Research Fellowship FG-2018-10936. Jacob Bortnik received funding from NASA grants NNX14AI18G, and RBSP-ECT and EMFISIS funding provided by JHU/APL contracts 967399 and 921647 under NASA's prime contract NAS5-01072.

This dataset contains fossil and modern pollen data collated during a workshop held in the UK in 2008 as part of the NERC (Quantifying and Understanding the Earth System) QUEST programme. The 96 sampling sites are located from 24°E (western Ukraine and Belarus) to easternmost Siberia, and lie north of latitude 40°N. The sample ages range from 21ka to present and are assigned to 1,000 year time slices. The dataset has been checked for consistent taxonomy and a redundancy-free taxonomy has been produced. Full details about this dataset can be found at https://doi.org/10.5285/6aeba247-52d1-4e84-949f-603742af40c1