NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Entropy Generation Across Earth's Bow ShockEarth's bow shock is a transition layer that causes an irreversible change in the state of plasma that is stationary in time. Theories predict entropy increases across the bow shock but entropy has never been directly measured. Cluster and Double Star plasma experiments measure 3D plasma distributions upstream and downstream of the bow shock that allow calculation of Boltzmann's entropy function H and his famous H-theorem, dH/dt ~ O. We present the first direct measurements of entropy density changes across Earth's bow shock. We will show that this entropy generation may be part of the processes that produce the non-thermal plasma distributions is consistent with a kinetic entropy flux model derived from the collisionless Boltzmann equation, giving strong support that solar wind's total entropy across the bow shock remains unchanged. As far as we know, our results are not explained by any existing shock models and should be of interests to theorists.
Document ID
20120002025
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Parks, George K. (California Univ. Berkeley, CA, United States)
McCarthy, Michael (Washington Univ. Seattle, WA, United States)
Fu, Suiyan (Peking Univ. Beijing, China)
Lee E. s (Kyunghee Univ. Suwon, Korea, Republic of)
Cao, Jinbin (BeiHan Univ. Beijing, China)
Goldstein, Melvyn L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Canu, Patrick (Ecole Polytechnique Paris, France)
Dandouras, Iannis S. (Centre d'Etude Spatiale des Rayonnements Toulouse, France)
Reme, Henri (Centre d'Etude Spatiale des Rayonnements Toulouse, France)
Fazakerley, Andrew (Mullard Space Science Lab. Dorking, United Kingdom)
Lin, Naiguo (California Univ. Berkeley, CA, United States)
Wilber, Mark (California Univ. Berkeley, CA, United States)
Date Acquired
August 25, 2013
Publication Date
December 4, 2011
Subject Category
Geophysics
Report/Patent Number
SH53B-2052
GSFC.ABS.5717.2011
Meeting Information
Meeting: American Geophysical Union 2011 Fall Meeting
Location: San Francisco, CA
Country: United States
Start Date: December 4, 2011
End Date: December 9, 2011
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available