Imperial College London
Alternate

Emeritus ProfessorStevenSchwartz

Faculty of Natural Sciences, Department of Physics

Distinguished Research Fellow
 
 
 
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Contact

 

s.schwartz Website

 
 
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Assistant

 

Mr Luke Kratzmann +44 (0)20 7594 7770

 
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Location

 

708BHuxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Broiles:2016:10.1002/2016JA022972,
author = {Broiles, TW and Livadiotis, G and Burch, JL and Chae, K and Clark, G and Cravens, TE and Davidson, R and Eriksson, A and Frahm, RA and Fuselier, SA and Goldstein, J and Goldstein, R and Henri, P and Madanian, H and Mandt, K and Mokashi, P and Pollock, C and Rahmati, A and Samara, M and Schwartz, SJ},
doi = {10.1002/2016JA022972},
journal = {Journal of Geophysical Research. Solid Earth},
pages = {7407--7422},
title = {Characterizing cometary electrons with kappa distributions},
url = {http://dx.doi.org/10.1002/2016JA022972},
volume = {121},
year = {2016}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The Rosetta spacecraft has escorted comet 67P/Churyumov-Gerasimenko since 6 August 2014and has offered an unprecedented opportunity to study plasma physics in the coma. We have usedthis opportunity to make thefirst characterization of cometary electrons with kappa distributions. Twothree-dimensional kappa functions werefit to the observations, which we interpret as two populations ofdense and warm (density=10cm3, temperature=2×105K, invariant kappa index=10>1000), andrarefied and hot (density=0.005cm3, temperature=5×105K, invariant kappa index=1–10) electrons. Wefit the observations on 30 October 2014 when Rosetta was 20km from 67P, and 3AU from the Sun. Werepeated the analysis on 15 August 2015 when Rosetta was 300km from the comet and 1.3AU from the Sun.Comparing the measurements on both days gives thefirst comparison of the cometary electron environmentbetween a nearly inactive comet far from the Sun and an active comet near perihelion. Wefind that the warmpopulation density increased by a factor of 3, while the temperature cooled by a factor of 2, and the invariantkappa index was unaffected. Wefind that the hot population density increased by a factor of 10, whilethe temperature and invariant kappa index were unchanged. We conclude that the hot population islikely the solar wind halo electrons in the coma. The warm population is likely of cometary origin, but itsmechanism for production is not known.
AU  - Broiles,TW
AU  - Livadiotis,G
AU  - Burch,JL
AU  - Chae,K
AU  - Clark,G
AU  - Cravens,TE
AU  - Davidson,R
AU  - Eriksson,A
AU  - Frahm,RA
AU  - Fuselier,SA
AU  - Goldstein,J
AU  - Goldstein,R
AU  - Henri,P
AU  - Madanian,H
AU  - Mandt,K
AU  - Mokashi,P
AU  - Pollock,C
AU  - Rahmati,A
AU  - Samara,M
AU  - Schwartz,SJ
DO  - 10.1002/2016JA022972
EP  - 7422
PY  - 2016///
SN  - 2169-9356
SP  - 7407
TI  - Characterizing cometary electrons with kappa distributions
T2  - Journal of Geophysical Research. Solid Earth
UR  - http://dx.doi.org/10.1002/2016JA022972
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000385811500006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/42807
VL  - 121
ER  -
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