Collisional and collisionless shocks

Ryutovl, D. D.

doi:10.1088/1361-6587/aaeccc

Title: Collisional and collisionless shocks

Full Record
Other Related Research

Abstract

Shock waves are one of the most common plasma phenomena. They play a significant role in astrophysical and magnetospheric environments, as well as in laboratory plasmas. The paper focuses on two issues that underline important similarities and dissimilarities between collisional and collisionless shocks. The two types of shocks are similar in that they can be formed by the overtaking mechanism. We demonstrate that geometrical structures appearing early in the process of shock formation from the generic smooth initial state are quite universal and similar in both cases. Characterization of these structures (dubbed here the “mussel-shell”) is presented. Alongside with these similarities, there exist also significant differences between the two types of shocks. The classical collisional shocks usually connect two well-defined equilibrium states (those before and after the shock transition). Each of these equilibrium states is characterized by the thermodynamic parameters of density, temperature, and pressure whose upstream and downstream values are related by the continuity of mass, momentum, and energy flux. In the collisionless plasmas, however, this description does not work: the final state can be any of the much broader class of states constrained only by the requirement of being stable with respect to collisionless plasma instabilities. To findmore »« less

Authors:

^[1]

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: Tue Nov 27 00:00:00 EST 2018

Research Org.:: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1497939

Report Number(s):: LLNL-JRNL-755606
Journal ID: ISSN 0741-3335; 942346

Grant/Contract Number:: AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Plasma Physics and Controlled Fusion

Additional Journal Information:: Journal Volume: 61; Journal Issue: 1; Journal ID: ISSN 0741-3335

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats


                    Ryutovl, D. D. Collisional and collisionless shocks.  United States: N. p., 2018. 
Web.  doi:10.1088/1361-6587/aaeccc.

Copy to clipboard


                    Ryutovl, D. D. Collisional and collisionless shocks.  United States.  https://doi.org/10.1088/1361-6587/aaeccc

Copy to clipboard


                    Ryutovl, D. D. Tue .  
"Collisional and collisionless shocks".  United States.  https://doi.org/10.1088/1361-6587/aaeccc.  https://www.osti.gov/servlets/purl/1497939.

Copy to clipboard


                    
@article{osti_1497939,

  title        = {Collisional and collisionless shocks},

  author       = {Ryutovl, D. D.},

  abstractNote = {Shock waves are one of the most common plasma phenomena. They play a significant role in astrophysical and magnetospheric environments, as well as in laboratory plasmas. The paper focuses on two issues that underline important similarities and dissimilarities between collisional and collisionless shocks. The two types of shocks are similar in that they can be formed by the overtaking mechanism. We demonstrate that geometrical structures appearing early in the process of shock formation from the generic smooth initial state are quite universal and similar in both cases. Characterization of these structures (dubbed here the “mussel-shell”) is presented. Alongside with these similarities, there exist also significant differences between the two types of shocks. The classical collisional shocks usually connect two well-defined equilibrium states (those before and after the shock transition). Each of these equilibrium states is characterized by the thermodynamic parameters of density, temperature, and pressure whose upstream and downstream values are related by the continuity of mass, momentum, and energy flux. In the collisionless plasmas, however, this description does not work: the final state can be any of the much broader class of states constrained only by the requirement of being stable with respect to collisionless plasma instabilities. To find a final state (which does not have to be Maxwellian) one now has to follow the evolution of the system through the whole transition, and a lot of universality is lost. In some situations even the separation of scales between the global flow and shock transition may be lost. Taken together, these phenomena reveal a fascinating interplay of hydrodynamics, statistical mechanics, and plasma physics.},

  doi          = {10.1088/1361-6587/aaeccc},

  journal      = {Plasma Physics and Controlled Fusion},

  number       = 1,

  volume       = 61,

  place        = {United States},

  year         = {Tue Nov 27 00:00:00 EST 2018},

  month        = {Tue Nov 27 00:00:00 EST 2018}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1088/1361-6587/aaeccc

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 2 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Experimental characterization of a transition from collisionless to collisional interaction between head-on-merging supersonic plasma jets^a)

Journal Article Moser, Auna L. ; Hsu, Scott C. - Physics of Plasmas

We present results from experiments on the head-on merging of two supersonic plasma jets in an initially collisionless regime for the counter-streaming ions [A. L. Moser & S. C. Hsu, Phys. Plasmas, submitted (2014)]. The plasma jets are of either an argon/impurity or hydrogen/impurity mixture and are produced by pulsed-power-driven railguns. Based on time- and space-resolved fast-imaging, multi-chord interferometry, and survey-spectroscopy measurements of the overlapping region between the merging jets, we observe that the jets initially interpenetrate, consistent with calculated inter-jet ion collision lengths, which are long. As the jets interpenetrate, a rising mean-charge state causes a rapid decrease inmore »« less
Cited by 23
https://doi.org/10.1063/1.4920955

Full Text Available
Experimental characterization of a transition from collisionless to collisional interaction between head-on-merging supersonic plasma jets

Journal Article Moser, Auna L., E-mail: mosera@fusion.gat.com ; Hsu, Scott C., E-mail: scotthsu@lanl.gov - Physics of Plasmas

We present results from experiments on the head-on merging of two supersonic plasma jets in an initially collisionless regime for the counter-streaming ions. The plasma jets are of either an argon/impurity or hydrogen/impurity mixture and are produced by pulsed-power-driven railguns. Based on time- and space-resolved fast-imaging, multi-chord interferometry, and survey-spectroscopy measurements of the overlapping region between the merging jets, we observe that the jets initially interpenetrate, consistent with calculated inter-jet ion collision lengths, which are long. As the jets interpenetrate, a rising mean-charge state causes a rapid decrease in the inter-jet ion collision length. Finally, the interaction becomes collisional andmore »« less
https://doi.org/10.1063/1.4920955
Semikinetic modeling of the outflow of ionospheric plasma through the topside collisional to collisionless transition region

Journal Article Wilson, G R - Journal of Geophysical Research; (United States)

The author applies a collisional semikinetic model to the study of the topside ionosphere transition region. In this study he considers the transition from (1) O{sup +} to H{sup +} dominance, (2) subsonic to supersonic H{sup +} flow, and (3) collisional to collisionless plasma. He focuses primarily on the H{sup +} ions as they flow upward from a relatively low altitude of 500-1,000 km to a high altitude of 7,000 km. These ions are subjected to collisions with O{sup +} ions and self collisions, as well as the effects of macroscopic forces such as the magnetic mirror force, gravity, andmore »« less
https://doi.org/10.1029/92JA00643
Observation of collisionless-to-collisional transition in colliding plasma jets with optical Thomson scattering

Journal Article Young, R. P. ; Kuranz, C. C. ; Froula, D. ; ... - Physics of Plasmas

Here we report on the results of an optical (526.5 nm) Thomson scattering investigation of low-Z (C₅H₈O₂) plasma jets created on the OMEGA laser. We were able to measure the plasma parameters of individual jets and investigate the nature of the interaction when two jets were collided head-on. This work demonstrates that the mass density of an individual jet increased from 10^-7 to 10^-4 g cm^-3, while the velocity fell from 300 to 100 km s over the probed time period (12–18 ns). When two jets were collided, we were able to capture the transition from collisionless interaction (interpenetration) tomore »« less
Cited by 5
https://doi.org/10.1063/1.5047218

Full Text Available
Laser plasma interaction studies in the context of shock ignition--Transition from collisional to collisionless absorption

Journal Article Klimo, O ; Centre Lasers Intenses et Applications, University Bordeaux 1-CEA-CNRS, Talence 33405 ; Tikhonchuk, V T ; ... - Physics of Plasmas

The shock ignition concept implies laser pulse intensities higher than 10{sup 15} W/cm{sup 2} (at the wavelength of 351 nm), which is the commonly accepted limit where the inverse bremsstruhlung absorption dominates. The transition from collisional to collisionless absorption in laser plasma interactions at higher intensities is studied in the present paper with the help of large scale one-dimensional particle-in-cell simulations. The initial parameters are defined by the hydrodynamic simulations corresponding to recent experiments. The simulations predict that a quasi-steady regime of laser plasma interaction is attained where the total laser energy absorption stays on the level of {approx}65% inmore »« less
https://doi.org/10.1063/1.3625264

Similar Records