DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Kinetic simulations of sheared flow stabilization in high-temperature Z-pinch plasmas

Journal Article · · Physics of Plasmas
DOI: https://doi.org/10.1063/1.5092241 · OSTI ID:1544963

We present that the first fully kinetic particle-in-cell (PIC) simulations of sheared flow stabilized Z-pinch plasmas show the suppression of the sausage instability by shear, ∂rvz ≠ 0, with flow Mach numbers ≲1, consistent with experimental observations. Experimental investigations of sheared-flow stabilized Z-pinches demonstrated stability for 10 s of microseconds, over 1000 Alfvén radial transit times, in quasi steady-state plasmas that are an intermediate between conventional inertial and magnetic confinement systems. The observed stability coincides with the presence of radial shear in axial flow profiles with peak speeds less than Mach 1, and experiments are underway to validate scaling this design to fusion conditions. The experimentally observed stability agrees with models of m = 1 kink mode suppression by sheared flows, but existing models of the m = 0 sausage mode underestimate the efficacy of sheared flow stabilization. These models rely on fluid approximations and find that stabilization requires flows ranging from Mach 1.7 to 4.3, and in some cases, stabilization is not reproduced in the models. This is faster than the measured flows in long-lived plasmas and would necessitate substantial energy convection out of the Z-pinch and the need to drive and sustain supersonic flows in future devices. The MHD models typically used in the literature are invalid in the high-temperature, high-current environments desirable for many Z-pinch applications, and they ignore large Larmor radius effects and viscous dissipation which are known to impact Z-pinch stability. PIC simulations can capture all these effects as well as kinetic instabilities that could influence the performance of high-temperature sheared flow stabilized Z-pinch plasmas. The PIC simulations presented here show the suppression and damping of m = 0 modes by sheared flows ∂rvz = 0.75vA/r0 with flow Mach numbers ≲1. Lastlyl, equivalent stability occurs under plasma conditions ranging from the limits of present-day experimental capabilities to the projected conditions of a sheared flow stabilized Z-pinch reactor.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Grant/Contract Number:
AC52-07NA27344; AR0000571
OSTI ID:
1544963
Report Number(s):
LLNL-JRNL--767536; 957144
Journal Information:
Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 26; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (41)

A Grid-Based Coulomb Collision Model for PIC Codes journal January 1996
Magneto-Inertial Fusion journal November 2015
A second-order implicit particle mover with adjustable damping journal October 1990
A pairwise nuclear fusion algorithm for weighted particle-in-cell plasma simulations journal July 2019
Stabilization of Z pinch by velocity shear journal November 2000
Linear analysis of sheared flow stabilization of global magnetohydrodynamic instabilities based on the Hall fluid model journal March 2002
Development of global magnetohydrodynamic instabilities in Z-pinch plasmas in the presence of nonideal effects journal May 2004
Formation of a sheared flow Z pinch journal June 2005
Effects of various axial flow profiles on the magneto-Rayleigh-Taylor instability in Z-pinch implosions journal June 2006
Pulsed-power-driven cylindrical liner implosions of laser preheated fuel magnetized with an axial field journal May 2010
Linear and nonlinear development of m=0 instability in a diffuse Bennett Z-pinch equilibrium with sheared axial flow journal July 2010
Characterization and focusing of light ion beams generated by ultra-intensely irradiated thin foils at the kilojoule scale journal May 2011
Species separation and kinetic effects in collisional plasma shocks journal May 2014
Design of magnetized liner inertial fusion experiments using the Z facility journal July 2014
Increasing plasma parameters using sheared flow stabilization of a Z-pinch journal May 2017
Hybrid-PIC modeling of laser-plasma interactions and hot electron generation in gold hohlraum walls journal June 2017
Kinetic effects on neutron generation in moderately collisional interpenetrating plasma flows journal January 2019
Effect of polarity on beam and plasma target formation in a dense plasma focus journal April 2019
The effect of sheared axial flow on the linear stability of the Z‐pinch journal February 1996
Linear stability of the collisionless, large Larmor radius Z-pinch journal July 1997
Equilibrium, flow shear and stability measurements in the Z-pinch journal July 2009
Hydromagnetic Instabilities of an Ideally Conducting Fluid journal January 1957
Ideal magnetohydrodynamic linear instabilities in the Z-pinch journal March 1988
Kinetic stability of the finite electron temperature Z -pinch journal April 1997
A review of the dense Z -pinch journal June 2011
Kinetic physics in ICF: present understanding and future directions journal April 2018
Magnetically Self-Focussing Streams journal June 1934
Theory of cumulative small-angle collisions in plasmas journal April 1997
Fully Kinetic Simulations of Dense Plasma Focus Z -Pinch Devices journal November 2012
Transition from Beam-Target to Thermonuclear Fusion in High-Current Deuterium Z -Pinch Simulations journal May 2016
Transition from Collisional to Collisionless Regimes in Interpenetrating Plasma Flows on the National Ignition Facility journal May 2017
Sustained Neutron Production from a Sheared-Flow Stabilized Z Pinch journal April 2019
Large Larmor radius stability of the z pinch journal April 1994
Sheared Flow Stabilization of the m = 1 Kink Mode in Z Pinches journal October 1995
Measurement of Instability Growth in a Magnetized Z Pinch in the Finite-Larmor-Radius Regime journal September 2001
Evidence of Stabilization in the Z -Pinch journal October 2001
Suppression of turbulence and transport by sheared flow journal January 2000
Spherically Imploding Plasma Liners as a Standoff Driver for Magnetoinertial Fusion journal May 2012
The Sheared-Flow Stabilized Z-Pinch journal January 2012
Measurement of Instability Growth in a Magnetized Z Pinch in the Finite-Larmor-Radius Regime text January 2001
Evidence of Stabilization in the Z-Pinch text January 2001

Cited By (3)

Retrospective of the ARPA-E ALPHA Fusion Program journal October 2019
Gyrokinetic simulations of m = 0 mode in sheared flow Z-pinch plasmas journal June 2019
Retrospective of the ARPA-E ALPHA fusion program text January 2019