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

Abstract

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 thatmore » 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:

Ofman, L.  ^[1];

• Search DOE PAGES for author "Ofman, L."
• Search DOE PAGES for ORCID "0000-0003-0602-6693"

Denton, R. E.  ^[2];

• Search DOE PAGES for author "Denton, R. E."
• Search DOE PAGES for ORCID "0000-0002-6398-337X"

Bortnik, J.  ^[3];

• Search DOE PAGES for author "Bortnik, J."
• Search DOE PAGES for ORCID "0000-0001-8811-8836"

An, X.  ^[3];

• Search DOE PAGES for author "An, X."
• Search DOE PAGES for ORCID "0000-0003-2507-8632"

Glocer, A.  ^[4];

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• Search DOE PAGES for ORCID "0000-0001-9843-9094"

Komar, C.  ^[1]

• Search DOE PAGES for author "Komar, C."
• Search DOE PAGES for ORCID "0000-0001-5850-7507"

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+ Show Author Affiliations

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:

Tue May 30 00:00:00 EDT 2017

Research Org.:

Univ. of California, Los Angeles, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1474282

Grant/Contract Number:  

SC0010578

Resource 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

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; EMIC waves; magnetospheric plasma; hybrid modeling; parametric study