Rights statement: ©2015. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Available under license: CC BY: Creative Commons Attribution 4.0 International License
Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Applying the cold plasma dispersion relation to whistler-mode chorus waves
T2 - EMFISIS wave measurements from the Van Allen Probes
AU - Hartley, Dave
AU - Chen, Yue
AU - Kletzing, C.A.
AU - Denton, Michael
AU - Kurth, William
N1 - ©2015. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
PY - 2015/2
Y1 - 2015/2
N2 - Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the the cold plasma dispersion relation in this context is tested using EMFISIS observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1-0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10¯3 nT2, using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater, 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.
AB - Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the the cold plasma dispersion relation in this context is tested using EMFISIS observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1-0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10¯3 nT2, using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater, 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.
KW - Van Allen Probes
KW - EMFISIS
KW - chorus waves
KW - wave-particle interactions
KW - radiation belts
KW - energetic electrons
U2 - 10.1002/2014JA020808
DO - 10.1002/2014JA020808
M3 - Journal article
VL - 120
SP - 1144
EP - 1152
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9402
IS - 2
ER -