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Title: Growth and nonlinear saturation of electromagnetic ion cyclotron waves in multi-ion species magnetospheric plasma

Here, the growth and saturation of electromagnetic ion cyclotron (EMIC) waves is essential to the magnetospheric dynamics. Determining and isolating the effects of multiple ion parameters such as temperatures, anisotropies, and relative abundances is important for quantifying these processes in the magnetospheric plasma. In order to study these process, we utilize a 2.5–D hybrid model (where ions are modeled with the particle–in–cell (PIC) method, and electrons are modeled as background neutralizing fluid) to study the nonlinear electromagnetic wave–particle interactions of hot H +, cold H +, cold He +, and cold or hot O + ions for a broad range of typical magnetospheric parameters. The excitation of EMIC waves is driven by the temperature anisotropy of hot H + in our model. As a result, we quantify the parametric dependence of the linear growth, the nonlinear saturation level of perpendicular magnetic fluctuations, and the temporal evolution of the ion temperature anisotropies. We establish the relation between key plasma parameters and the saturated EMIC wave power, using either power law fits or a nonlinear regression method. We construct the dispersion relation of the waves using the results of the model and investigate the energy content in the various branches of themore » dispersion ( k –ω space), showing that the different modes can generate wave power in different regions of k space. We find that large O + concentration reduces the growth and saturated amplitude of the waves; but the waves are less sensitive to the temperature of the O + in the temperature range relevant to the magnetosphere.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [1]
  1. Catholic Univ. of America, Washington, D.C. (United States); NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  2. Dartmouth College, Hanover, NH (United States)
  3. Univ. of California, Los Angeles, CA (United States)
  4. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
Publication Date:
Grant/Contract Number:
SC0010578
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 6; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Research Org:
Univ. of California, Los Angeles, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; EMIC waves; magnetospheric plasma; hybrid modeling; parametric study
OSTI Identifier:
1474282

Ofman, L., Denton, R. E., Bortnik, J., An, X., Glocer, A., and Komar, C.. Growth and nonlinear saturation of electromagnetic ion cyclotron waves in multi-ion species magnetospheric plasma. United States: N. p., Web. doi:10.1002/2017JA024172.
Ofman, L., Denton, R. E., Bortnik, J., An, X., Glocer, A., & Komar, C.. Growth and nonlinear saturation of electromagnetic ion cyclotron waves in multi-ion species magnetospheric plasma. United States. doi:10.1002/2017JA024172.
Ofman, L., Denton, R. E., Bortnik, J., An, X., Glocer, A., and Komar, C.. 2017. "Growth and nonlinear saturation of electromagnetic ion cyclotron waves in multi-ion species magnetospheric plasma". United States. doi:10.1002/2017JA024172. https://www.osti.gov/servlets/purl/1474282.
@article{osti_1474282,
title = {Growth and nonlinear saturation of electromagnetic ion cyclotron waves in multi-ion species magnetospheric plasma},
author = {Ofman, L. and Denton, R. E. and Bortnik, J. and An, X. and Glocer, A. and Komar, C.},
abstractNote = {Here, the growth and saturation of electromagnetic ion cyclotron (EMIC) waves is essential to the magnetospheric dynamics. Determining and isolating the effects of multiple ion parameters such as temperatures, anisotropies, and relative abundances is important for quantifying these processes in the magnetospheric plasma. In order to study these process, we utilize a 2.5–D hybrid model (where ions are modeled with the particle–in–cell (PIC) method, and electrons are modeled as background neutralizing fluid) to study the nonlinear electromagnetic wave–particle interactions of hot H+, cold H+, cold He+, and cold or hot O+ ions for a broad range of typical magnetospheric parameters. The excitation of EMIC waves is driven by the temperature anisotropy of hot H+ in our model. As a result, we quantify the parametric dependence of the linear growth, the nonlinear saturation level of perpendicular magnetic fluctuations, and the temporal evolution of the ion temperature anisotropies. We establish the relation between key plasma parameters and the saturated EMIC wave power, using either power law fits or a nonlinear regression method. We construct the dispersion relation of the waves using the results of the model and investigate the energy content in the various branches of the dispersion (k∥–ω space), showing that the different modes can generate wave power in different regions of k space. We find that large O+ concentration reduces the growth and saturated amplitude of the waves; but the waves are less sensitive to the temperature of the O+ in the temperature range relevant to the magnetosphere.},
doi = {10.1002/2017JA024172},
journal = {Journal of Geophysical Research. Space Physics},
number = 6,
volume = 122,
place = {United States},
year = {2017},
month = {5}
}