1. PROJECT ------------ Title: Modelling the acceleration, transport and loss of radiation belt electrons to protect satellites from space weather (Rad-Sat) Dates: May 2017 - April 2021 Funding organisation: NERC Grant no.: NE/P017274/1 2. DATASET ------------ Title: PADIE diffusion coefficients for plasmaspheric hiss Description: This dataset contains a large number of quasilinear diffusion coefficients that describe the efficacy of wave-particle interactions in the collisionless plasma of Earth's inner magnetosphere. The individual diffusion coefficients are calculated using the PADIE software at the British Antarctic Survey in Cambridge. Glauert, S. A., and Horne, R. B. (2005), Calculation of pitch angle and energy diffusion coefficients with the PADIE code, J. Geophys. Res., 110, A04206, doi:10.1029/2004JA010851. Input information (wave intensity and plasma to gyrofrequency ratio) are obtained from co-located and simultaneous observations from Van Allen Probe A as it travelled through a region of space between 0900 and 1000 MLT, and from -5 to +5 degrees magnetic longitude during the period September 2012 - June 2016. There are three locations in L*: L*=2.5+/-0.05; L* = 3.0+/-0.05 and L*=3.5+/-0.05. Diffusion coefficients are calculated separately for each set of co-located measurements, for the mean wave intensity and varying plasma to gyrofrequency ratio, and for the mean plasma to gyrofrequency ratio and varying wave intensity. The distribution of coefficients gives some indication of the variability of the wave-particle interaction due to plasmaspheric hiss and illustrates improvements that can be made to models of wave-particle interactions in Radiation Belt diffusion models. Publication Year: 2019 Creators: Dr Clare Watt, Hayley Allison, Dr Sarah Glauert and Dr Nigel Meredith Organisations: University of Reading and British Antarctic Survey Rights-holders: University of Reading, Hayley Allison, British Antarctic Survey 3. TERMS OF USE ----------------- This dataset is licensed by the rights-holders under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/. 4. CONTENTS ------------ File listing There are three folders of files labelled by the L* value of the bin. Each diffusion coefficient calculation is provided in a separate file with the following naming conventions: 500.000keVXXX.out All files beginning "500.000keV" provide the quasilinear diffusion coefficient calculated for each observed co-located and simultaneous wave intensity and plasma to gyrofrequency ratio pair. XXX indicates the index of the measurement. meanBwaveXXX.out All files beginning "meanBwave" provide the quasilinear diffusion coefficient calculated for each observed plasma to gyrofrequency ratio and for the mean (average) wave intensity. Again, XXX indicates the index of the measurement. meanfpefceXXX.out All files beginning "meanfpefce" provide the quasilinear diffusion coefficient calculated for each wave intensity observation, and for the mean (average) plasma to gyrofrequency ratio. Again, XXX indicates the index of the measurement. means.out This file contains the diffusion coefficient calculated from the mean values of the input parameters observed in this bin. medians.out This file contains the diffusion coefficient calculated from the median values of the input parameters observed in this bin. Files are provided in ASCII format. The header information includes other parameters used by PADIE as well as version number and source. This information includes specification of the planetary magnetic environment and type of magnetic field model; the composition of the plasma, the plasma species interacting with the waves and wave type; number of resonances included; particle energy; normalising factors; wave amplitude model; wave frequency model; extent of the wave region. Diffusion coefficients are listed as a function of pitch-angle and both pitch-angle and momentum space diffusion coefficients are given. 5. METHOD and PROCESSING -------------------------- Diffusion coefficients are generated using the Pitch-Angle Diffusion of Ions and Electrons (PADIE) algorithm (https://www.bas.ac.uk/science/research-models/padie-pitch-angle-diffusion-of-ions-and-electrons/). Glauert, S. A., and Horne, R. B. (2005), Calculation of pitch angle and energy diffusion coefficients with the PADIE code, J. Geophys. Res., 110, A04206, doi:10.1029/2004JA010851. PADIE uses the quasilinear theory of collisionless plasma to generate diffusion coefficients that describe the efficacy of wave-particle interactions in tenuous, simple plasma. The resulting distributions of diffusion coefficients calculated using observations from an extended multi-year period are discussed in C. E. J. Watt, H. Allison, N. P. Meredith, R. L. Thompson, S. N. Bentley, I. J. Rae, S. A. Glauert, and R. B. Horne, "Variability of Quasilinear Diffusion Coefficients for Plasmaspheric Hiss", JGR - Space Physics, under review (2019).