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Title: The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries: Plasma Sheet Ion Composition

Abstract

The ion plasma sheet (~few hundred eV to ~few 10s keV) is usually dominated by H + ions. Here, changes in ion composition within the plasma sheet are explored both during individual events, and statistically during 54 calm-to-storm events and during 21 active-to-calm events. Ion composition data from the HOPE (Helium, Oxygen, Proton, Electron) instruments onboard Van Allen Probes satellites provide exceptional spatial and temporal resolution of the H +, O +, and He + ion fluxes in the plasma sheet. H+ shown to be the dominant ion in the plasma sheet in the calm-to-storm transition. However, the energy-flux of each ion changes in a quasi-linear manner during extended calm intervals. Heavy ions (O + and He +) become increasingly important during such periods as charge-exchange reactions result in faster loss for H + than for O + or He +. Results confirm previous investigations showing that the ion composition of the plasma sheet can be largely understood (and predicted) during calm intervals from knowledge of: (a) the composition of previously injected plasma at the onset of calm conditions, and (b) use of simple drift-physics models combined with calculations of charge-exchange losses.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [4]; ORCiD logo [4]; ORCiD logo [4]; ORCiD logo [4]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [6]
  1. New Mexico Consortium, Los Alamos, NM (United States); Space Science Inst., Boulder, CO (United States). Center for Plasma Physics
  2. Planetary Science Inst., Tuscon, AZ (United States)
  3. New Mexico Consortium, Los Alamos, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  6. Univ. of New Hampshire, Durham, NH (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
National Aeronautic and Space Administration (NASA); USDOE
OSTI Identifier:
1402646
Report Number(s):
LA-UR-17-26020
Journal ID: ISSN 2169-9380; TRN: US1703018
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Name: Journal of Geophysical Research. Space Physics; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Heliospheric and Magnetospheric Physics

Citation Formats

Denton, M. H., Thomsen, M. F., Reeves, G. D., Larsen, B. A., Henderson, M. G., Jordanova, V. K., Fernandes, P. A., Friedel, R. H. W., Skoug, R. M., Funsten, H. O., MacDonald, E. A., and Spence, H. A. The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries: Plasma Sheet Ion Composition. United States: N. p., 2017. Web. doi:10.1002/2017JA024475.
Denton, M. H., Thomsen, M. F., Reeves, G. D., Larsen, B. A., Henderson, M. G., Jordanova, V. K., Fernandes, P. A., Friedel, R. H. W., Skoug, R. M., Funsten, H. O., MacDonald, E. A., & Spence, H. A. The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries: Plasma Sheet Ion Composition. United States. doi:10.1002/2017JA024475.
Denton, M. H., Thomsen, M. F., Reeves, G. D., Larsen, B. A., Henderson, M. G., Jordanova, V. K., Fernandes, P. A., Friedel, R. H. W., Skoug, R. M., Funsten, H. O., MacDonald, E. A., and Spence, H. A. 2017. "The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries: Plasma Sheet Ion Composition". United States. doi:10.1002/2017JA024475.
@article{osti_1402646,
title = {The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries: Plasma Sheet Ion Composition},
author = {Denton, M. H. and Thomsen, M. F. and Reeves, G. D. and Larsen, B. A. and Henderson, M. G. and Jordanova, V. K. and Fernandes, P. A. and Friedel, R. H. W. and Skoug, R. M. and Funsten, H. O. and MacDonald, E. A. and Spence, H. A.},
abstractNote = {The ion plasma sheet (~few hundred eV to ~few 10s keV) is usually dominated by H+ ions. Here, changes in ion composition within the plasma sheet are explored both during individual events, and statistically during 54 calm-to-storm events and during 21 active-to-calm events. Ion composition data from the HOPE (Helium, Oxygen, Proton, Electron) instruments onboard Van Allen Probes satellites provide exceptional spatial and temporal resolution of the H+, O+, and He+ ion fluxes in the plasma sheet. H+ shown to be the dominant ion in the plasma sheet in the calm-to-storm transition. However, the energy-flux of each ion changes in a quasi-linear manner during extended calm intervals. Heavy ions (O+ and He+) become increasingly important during such periods as charge-exchange reactions result in faster loss for H+ than for O+ or He+. Results confirm previous investigations showing that the ion composition of the plasma sheet can be largely understood (and predicted) during calm intervals from knowledge of: (a) the composition of previously injected plasma at the onset of calm conditions, and (b) use of simple drift-physics models combined with calculations of charge-exchange losses.},
doi = {10.1002/2017JA024475},
journal = {Journal of Geophysical Research. Space Physics},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

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  • The first simultaneous study of dc and ac electric and magnetic fields, E x B velocity, plasma flows, ..beta.., total energy density, energetic particles, and ion composition from the ISEE satellites and ground and interplanetary magnetic fields has been made to determine (1) the relationship of the previously observed electric fields at the plasma sheet boundary and at the neutral sheet to plasma parameters, and (2) whether the phenomena occurring during quiet and active times were consistent with the formation of a near-earth neutral line during substorms or with the boundary layer model. The following observations during the two substormsmore » studied are in agreement with predictions of the neutral-line model: (1) the buildup of energy stored in the tail magnetic field for 1-2 hours prior to onset, followed by its rapid decrease after onset, (2) the enhanced convection of magnetic field lines and plasma into the neutral sheet from above and below as indicated by the E x B velocity, (3) tailward convection of field lines and plasma (E-italic/sub y/(dawnward and duskward) and B-italic/sub z-italic/ (northward and southward) anticorrelated in sign) at onset, followed by thinning of the plasma sheet, and then convection earthward (E-italic/sub y-italic/ and B-italic/sub z-italic/ correlated in sign) during recovery of the plasma sheet, (4) repeated encounters with the neutral sheet during the times of the large electric fields and fast plasma flows, indicating that both existed throughout the plasma sheet and not just at the boundary and that the substorm-associated phenomena were initiated (5) heating of electrons in association with fast tailward flow and southward B-italic/sub z-italic/.« less
  • The procedure for the determination of {sup 99}Tc inductively coupled plasma-mass spectrometry (ICP-MS) was based on the modification of a variety of available separation techniques. Standard Ru and Rh solutions were used for checking decontaminations and instrument response respectively. Technetium-99 and {sup 95m}Tc tracers were applied as yield monitors using ICP-MS and gamma-ray spectrometry respectively. Percent recoveries are reported for a variety of radiochemical separation procedures for water (58-83%), seaweed (10-76%), and for soil matrices (19-79%).
  • Data from the Plasma Composition Experiment on ISSE 1, covering the energy range 0.1--16 keV/e, show that a dramatic change took place in the plasma sheet ion composition in conjunction with the magnetic substorm activity on March 22, 1979. Beginning about 1124 UT the ion population at the ISEE 1 location changed from what appeared to be predominantly ions from the solar wind to a mixture of comparable numbers of solar wind and terrestrial ions. ISEE 1 was inbound in the predawn sector during this time, and the plasma composition experiment provided data from Rapprox. =21 R/sub E/ and LTapprox.more » =0130, down to Rapprox. =3 R/sub E/ and LTapprox. =0530. Prior to the substorm activity about 90--95% of the ion density was due to H/sup +/ and He/sup + +/ ions, which appeared to be mostly of solar wind origin. The H/sup +/ and He/sup + +/ components, each approximated by a Maxwell-Boltzmann distribution, had a temperature ratio T(He/sup + +/)/T(H/sup +/)approx. =4 and a density ratio n(He/sup + +/)/n(H/sup +/)approx. =1.5--3%. Both values are consistent with measurements made concurrently in the solar wind by the plasma experiment on ISSE 3. The remaining 5--10% of the density was due mainly to O/sup +/ and He/sup +/ ions of ionospheric origin. All four ion populations had broad energy spectra with mean energies of several keV/e.« less
  • A large statistical survey of the 0.1- to 16-keV/e plasma sheet ion composition has been carried out using data obtained by the Plasma Composition Experiment on ISEE 1 between 10 and 23 R/sub E/ during 1978 and 1979. This survey includes more than 10 times the quantity of data used in earlier studies of the same topic and makes it possible to investigate in finer detail the relationship between the ion composition and the substorm activity. The larger data base also makes it possible for the first time to study the spatial distribution of the principal ion species. As foundmore » in previous studies, the ion composition has a large variance at any given value of the AE index, but a number of distinct trends emerge when the data are averaged at each activity level. During quiet conditions the plasma sheet is dominated by ions of solar origin (H/sup +/ and He/sup + +/), as found in earlier studies, and these ions are most numerous during extended periods of very low activity (AE< or approx. =30 ..gamma..). The quiet time density of these ions is particularly large in the flanks of the plasma sheet (GSM Yapprox. +- 10 R/sub E/), where it is about twice as large as it is near the central axis of the plasma sheet (Y = Z = 0). In contrast, the energy of these ions peaks near the central axis.« less
  • Data obtained from the energetic ion mass spectrometer experiment on Isee 1 in the distant plasma sheet are presented. These data show that (1) the plasma sheet has a significant and variable ionospheric component (H/sup +/ and O/sup +/) representing from 10% to more than 50% of the total number density and (2) there is more than one process responsible for the energization of solar wind plasma (H/sup +/ and He/sup + +/) to plasma sheet energies.