@article{Goldman:2020:10.1029/2020JA028340,
author = {Goldman, MV and Newman, DL and Eastwood, JP and Lapenta, G},
doi = {10.1029/2020JA028340},
journal = {Journal of Geophysical Research: Space Physics},
pages = {1--19},
title = {Multibeam energy moments of multibeam particle velocity distributions},
url = {http://dx.doi.org/10.1029/2020JA028340},
volume = {125},
year = {2020}
}

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TY  - JOUR
AB  - Highresolution electron and ion velocity distributions, f(v), which consist of N effectively disjoint beams, have been measured by NASA's Magnetospheric Multiscale Mission and in reconnection simulations. Commonly used standard velocity moments assume a single meanflow velocity for the entire distribution. This can lead to counterintuitive results for a multibeam f(v). An example is the standard thermal energy density moment (at a given spacetime point) of a pair of equal and opposite cold particle beams. This standard moment is nonzero even though each beam has zero thermal energy density. By contrast, a multibeam moment of two or more cold beams at a given position and time has no thermal energy. A multibeam moment is obtained by taking a standard moment of each beam and then summing over beams. In this paper we will generalize these notions, explore their consequences, and apply them to an f(v) which is a sum of triMaxwellians. Both standard and multibeam energy moments have coherent and incoherent pieces. Examples of incoherent moments are the thermal energy density, the pressure, and the thermal energy flux (enthalpy flux plus heat flux). Corresponding coherent moments are the bulk kinetic energy density, the ram pressure, and the bulk kinetic energy flux. The difference between a standard incoherent moment and its multibeam counterpart will be defined as the “pseudothermal part” of the standard moment. The sum of a pair of corresponding coherent and incoherent moments is the undecomposed moment. Undecomposed standard moments are always equal to the corresponding undecomposed multibeam moments.
AU  - Goldman,MV
AU  - Newman,DL
AU  - Eastwood,JP
AU  - Lapenta,G
DO  - 10.1029/2020JA028340
EP  - 19
PY  - 2020///
SN  - 2169-9380
SP  - 1
TI  - Multibeam energy moments of multibeam particle velocity distributions
T2  - Journal of Geophysical Research: Space Physics
UR  - http://dx.doi.org/10.1029/2020JA028340
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000603639900019&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JA028340
UR  - http://hdl.handle.net/10044/1/85860
VL  - 125
ER  - 

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