Pressure and Energy Balance of Stagnating Plasmas in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>z</mml:mi></mml:math>-Pinch Experiments: Implications to Current Flow at Stagnation

Maron, Y.; Starobinets, A.; Fisher, V.; Kroupp, E.; Osin, D.; Fisher, A.; Deeney, C.; Coverdale, C. A.; LePell, P.D.; Yu, Edmund; Jennings, C. A.; Cuneo, M. E.; Herrmann, Mark; Porter, J. L.; Mehlhorn, T. A.; Apruzese, J. P.

doi:10.1103/physrevlett.111.035001

Cited by 40 publications

(37 citation statements)

References 21 publications

(40 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present work also neglects magnetic field effects, in line with other studies of turbulence in 3D compressions [7,8]. This, too, limits the applicability to Z-pinch compressions, though there are also many instances in which the magnetic field need not dominate the dynamics in a Zpinch [6].…”

Section: Introductionsupporting

confidence: 58%

“…Note that while these gas-puff Z-pinches appear to have substantial non-radial TKE even at stagnation [6], turbulence in the hot spot of ignition shots at the National Ignition Facility (NIF) is expected to be dissipated by high viscosity [8]. The much higher temperatures in these hot spots create this high viscosity, but they are assisted by fuel of Z = 1, to the extent it is not contaminated by mix.…”

Section: Introductionmentioning

confidence: 99%

“…The plasma in magnetically driven [2,[4][5][6] or laser driven [7,8] compressions can be turbulent. There can be substantial reduction in viscosity growth due to increasing ionization state for a gas-puff Z-pinch.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Compressing turbulence and sudden viscous dissipation with compression-dependent ionization state

Davidovits

Fisch

2016

Phys. Rev. E

View full text Add to dashboard Cite

Turbulent plasma flow, amplified by rapid 3D compression, can be suddenly dissipated under continuing compression. This effect relies on the sensitivity of the plasma viscosity to the temperature, µ ∼ T 5/2 . The plasma viscosity is also sensitive to the plasma ionization state. We show that the sudden dissipation phenomenon may be prevented when the plasma ionization state increases during compression, and demonstrate the regime of net viscosity dependence on compression where sudden dissipation is guaranteed. Additionally, it is shown that, compared to cases with no ionization, ionization during compression is associated with larger increases in turbulent energy, and can make the difference between growing and decreasing turbulent energy.

show abstract

Section: Introductionsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Compressing turbulence and sudden viscous dissipation with compression-dependent ionization state

Davidovits

Fisch

2016

Phys. Rev. E

View full text Add to dashboard Cite

show abstract

“…This behavior occurs in plasma, but is not predicted by studies of neutral gas compression [7][8][9][10][11][12][13]. In fact, it was observations of the dominant effect of the TKE in Zpinches, both in pressure balance [4] and in radiation balance [2,4], that stimulated the present study.Compression is rapid if the rate of compression is fast compared to the turbulent timescale τ = k/ with k the TKE and the viscous dissipation rate. In the initially rapid plasma compressions here, the viscous dissipation eventually grows such that the turbulent timescale τ shortens, and the plasma TKE suddenly dissipates.…”

mentioning

confidence: 69%

“…The plasma motion in these compressions can be turbulent, whether magnetically driven [1][2][3][4] or laser driven [5,6]. However, rapid compression of this turbulent plasma, where the viscosity is highly sensitive to temperature, is demonstrated here to exhibit unusual behavior, where the turbulent kinetic energy (TKE) abruptly switches from growing to rapidly dissipating.…”

mentioning

confidence: 82%

Sudden Viscous Dissipation of Compressing Turbulence

Davidovits

Fisch

2016

Phys. Rev. Lett.

View full text Add to dashboard Cite

Compression of turbulent plasma can amplify the turbulent kinetic energy, if the compression is fast compared to the viscous dissipation time of the turbulent eddies. A sudden viscous dissipation mechanism is demonstrated, whereby this amplified turbulent kinetic energy is rapidly converted into thermal energy, suggesting a new paradigm for fast ignition inertial fusion.Introduction.-Unprecedented densities and temperatures are now reached by compressing plasma using lasers or magnetic fields, with the objective of reaching nuclear fusion, prodigious x-ray production, or new regimes of materials. The plasma motion in these compressions can be turbulent, whether magnetically driven [1][2][3][4] or laser driven [5,6]. However, rapid compression of this turbulent plasma, where the viscosity is highly sensitive to temperature, is demonstrated here to exhibit unusual behavior, where the turbulent kinetic energy (TKE) abruptly switches from growing to rapidly dissipating. This behavior occurs in plasma, but is not predicted by studies of neutral gas compression [7][8][9][10][11][12][13]. In fact, it was observations of the dominant effect of the TKE in Zpinches, both in pressure balance [4] and in radiation balance [2,4], that stimulated the present study.Compression is rapid if the rate of compression is fast compared to the turbulent timescale τ = k/ with k the TKE and the viscous dissipation rate. In the initially rapid plasma compressions here, the viscous dissipation eventually grows such that the turbulent timescale τ shortens, and the plasma TKE suddenly dissipates. This dissipation is sudden in that it occurs over a time interval that is small compared to the overall compression time.This sudden dissipation mechanism now suggests a new fast ignition paradigm. Imagine an initially turbulent fusion fuel plasma where the majority of the energy is in the turbulent motion. This plasma is then rapidly compressed, causing both the TKE and thermal energy to grow, while the TKE retains most of the energy, as observed in certain Z-pinch experiments [1][2][3][4]. Since radiation losses (both synchrotron and bremsstrahlung) and nuclear fusion are dependent on thermal energy but not the TKE, those processes are minimized under such compression, since the plasma stays comparatively cool. However, late in the compression, the TKE suddenly dissipates viscously into thermal energy, thereby igniting the plasma without having undergone large radiation losses.In neutral gas, upon rapid compression, the TKE grows. In an isotropic 3D compression, it grows as 1/L 2 , where L is the (time dependent) side length of a box that is compressing with the mean flow along each axis. This is true for both the zero Mach case [7], where the TKE is solenoidal, as well as in the finite Mach case, where the TKE has both solenoidal and dilational components, which each grow in energy as 1/L 2 [12]. This is the same

show abstract