Force-Free Current Flow in Z Pinches Imploded in an Axial Magnetic Field

Velikovich, A. L.; Ouart, N. D.; Giuliani, J. L.; Baksht, R. B.; Rousskikh, A. G.; Oreshkin, V. I.; Mikitchuk, D.; Cvejić, M.; Doron, R.; Kroupp, E.; Maron, Y.

doi:10.1109/plasma.2017.8496380

Cited by 3 publications

(7 citation statements)

References 2 publications

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“…On the contrary, when the resistivity decreases with increasing temperature, as is the case of a plasma, the growth of thermal instabilities should lead to the formation of individual current channels. This is exactly what is observed in experiments with imploding plasma liners [25][26][27][28][29][30][31][32], and filaments are also detected in the plasma affected by the axial magnetic field [25,26,31].…”

Section: Introductionsupporting

confidence: 86%

“…Figure 5 shows regions in the plane ni j , T in which TF instabilities can be stabilized due to radiative losses. The regions in which condition (28) are satisfied are highlighted in blue (I) and the regions in which both conditions (28,29) are satisfied simultaneously are highlighted in green (II). As can be seen from figure 5, condition ( 29) is stronger than condition (28), that is, it is not satisfied at high temperatures in contrast to condition (28).…”

Section: The Model Of Filamentation Taking Account Of Radiative Lossesmentioning

confidence: 99%

“…The regions in which condition (28) are satisfied are highlighted in blue (I) and the regions in which both conditions (28,29) are satisfied simultaneously are highlighted in green (II). As can be seen from figure 5, condition ( 29) is stronger than condition (28), that is, it is not satisfied at high temperatures in contrast to condition (28). Comparing figure 5 with figure 4, we see that the stabilization of TF instabilities due to radiative losses occurs mainly in those regions where radiative losses prevail over Joule energy input.…”

Section: The Model Of Filamentation Taking Account Of Radiative Lossesmentioning

confidence: 99%

“…However, the presence of an axial magnetic field does not prevent the growth of other types of instabilities, particularly filamentation instabilities. Instabilities of this type, manifesting themselves as individual current channels, are often observed in plasma focus [21][22][23][24] and Z-pinch experiments [25][26][27][28][29][30][31][32]. To study the mechanism of growth of filamentation instabilities is relevant for the implementation of the MagLIF concept for the following reason.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the plasma self-radiation on the growth of thermal filamentation instabilities in imploding Z pinches

Oreshkin¹,

Oreshkin²

2021

Plasma Phys. Control. Fusion

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The development of thermal filamentation (TF) instabilities in a current-carrying plasma shell under the action of the plasma self-radiation was analyzed in terms of a small perturbation theory. A stationary collisional radiative model was used to calculate the parameters of the bremsstrahlung, recombination radiation, and spectral line radiation. It has been shown that radiative losses can either enhance or weaken the growth of TF instabilities. The pattern of the effect is governed by the dependence of the energy lost by the plasma due to radiation, Q Rad, on the plasma temperature T. If Q Rad increases slower than ∼T, the radiative losses enhance TF instabilities. In the opposite case, that is when Q Rad increases faster than ∼T, the radiative losses lead to suppression of TF instabilities. When the energy lost due to radiation is greater than the Joule energy input, TF instabilities can be completely stabilized due to radiation. The plasma parameter ranges for which stabilization of TF instabilities may occur due to radiation have been found for aluminum and argon.

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Section: Introductionsupporting

confidence: 86%

Section: The Model Of Filamentation Taking Account Of Radiative Lossesmentioning

confidence: 99%

Section: The Model Of Filamentation Taking Account Of Radiative Lossesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of the plasma self-radiation on the growth of thermal filamentation instabilities in imploding Z pinches

Oreshkin¹,

Oreshkin²

2021

Plasma Phys. Control. Fusion

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“…However, even when the above stabilization methods are used, another type of instability may develop at the initial stage of compression, namely, filamentation, which shows up as the formation of individual current channels [28][29][30][31][32][33][34]. Filaments may occur both in cascaded liners [30,31] and in liners with an axial magnetic field [28][29][30][31][32]. A probable reason for the occurrence of filaments is the development of thermal instabilities.…”

Section: Introductionmentioning

confidence: 99%

Thermal filamentation instabilities developing in imploding plasma liners

Oreshkin

Baksht

Oreshkin

et al. 2020

Plasma Phys. Control. Fusion

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Filamentation is a type of magnetohydrodynamic instability that may develop in a currentcarrying plasma. It is supposed that filaments, individual current channels, are formed due to thermal instabilities. The growth of these instabilities is determined by the behavior of the electrical conductivity of the material depending on its thermodynamic parameters. If the conductivity increases with temperature, as is the case in a plasma, thermal instabilities should give rise to the formation of separate current channels. This paper presents an analysis of the development of thermal instabilities in imploding plasma liners performed in terms of small perturbation theory. The theoretical predictions are compared with the results of experiments conducted on the IMRI-5 facility at a current of amplitude up to 450 kA and rise time about 500 ns.

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