Title: Electron cyclotron drift instability and anomalous transport: two-fluid moment theory and modeling

Abstract

In the presence of a strong electric field perpendicular to the magnetic field, the electron cross-field (E × B) flow relative to the unmagnetized ions can cause the so-called electron cyclotron drift instability (ECDI) due to resonances of the ion acoustic mode and the electron cyclotron harmonics. This occurs in, for example, collisionless shock ramps in space, and in E × B discharge devices such as Hall thrusters. A prominent feature of ECDI is its capability to induce an electron flow parallel to the background >E field at a speed greatly exceeding predictions by classical collision theory. Such anomalous transport is important due to its role in particle thermalization at space shocks, and in causing plasma flows towards the walls of E × B devices, leading to unfavorable erosion and performance degradation, etc. The development of ECDI and anomalous transport is often considered requiring a fully kinetic treatment. In this work, however, we demonstrate that a reduced variant of this instability, and more importantly, the associated anomalous transport, can be treated self-consistently in a collisionless two-fluid framework without any adjustable collision parameter. By treating both electron and ion species on an equal footing, the free energy due to the inter-speciesmore » velocity shear allows the growth of an anomalous electron flow parallel to the background E field. We will first present linear analyses of the instability in the two-fluid five- and ten-moment models, and compare them against the fully-kinetic theory. At low temperatures, the two-fluid models predict the fastest-growing mode in good agreement with the kinetic result. Also, by including more (> = 10) moments, secondary (and possibly higher) unstable branches can be recovered. The dependence of the instability on ion-to-electron mass ratio, plasma temperature, and background B field strength is also thoroughly explored. We then carry out direct numerical simulations of the cross-field setup using the five-moment model. The development of the instability, as well as the anomalous transport, is confirmed and in excellent agreement with theoretical predictions. The force balance properties are also studied using the five-moment simulation data. Here this work casts new insights into the nature of ECDI and the associated anomalous transport and demonstrates the potential of the two-fluid moment model in efficient modeling of E × B plasmas.« less

Authors:

Wang, Liang  ^[1];

• Search DOE PAGES for author "Wang, Liang"
• Search DOE PAGES for ORCID "0000-0003-4821-3120"

Hakim, Ammar  ^[2];

• Search DOE PAGES for author "Hakim, Ammar"
• Search DOE PAGES for ORCID "0000-0001-6603-8595"

Juno, James  ^[2];

• Search DOE PAGES for author "Juno, James"
• Search DOE PAGES for ORCID "0000-0001-6835-273X"

Srinivasan, Bhuvana  ^[3]

• Search DOE PAGES for author "Srinivasan, Bhuvana"
• Search DOE PAGES for ORCID "0000-0002-0712-1097"

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+ Show Author Affiliations

1. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Princeton University, NJ (United States)
2. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
3. Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA (United States)

Publication Date:

Fri Sep 30 00:00:00 EDT 2022

Research Org.:

Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program; US Air Force Office of Scientific Research (AFOSR); National Science Foundation (NSF)

OSTI Identifier:

1963008

Grant/Contract Number:  

AC02-09CH11466; FA9550-15-1-0193; PHY-1847905; AGS-2019828; AC02-09CH1146

Resource Type:

Accepted Manuscript

Journal Name:

Plasma Sources Science and Technology

Additional Journal Information:

Journal Volume: 31; Journal Issue: 10; Journal ID: ISSN 0963-0252

Publisher:

IOP Publishing

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY