arXiv: Plasma Physics最新文献_第7页

Fire-hose instability of inhomogeneous plasma flows with heat fluxes 带热通量的非均匀等离子体流的消防水带不稳定性

arXiv: Plasma Physics Pub Date : 2020-05-08 DOI: 10.1063/5.0013490

E. Uchava, A. Tevzadze, B. Shergelashvili, N. S. Dzhalilov, S. Poedts

{"title":"Fire-hose instability of inhomogeneous plasma flows with heat fluxes","authors":"E. Uchava, A. Tevzadze, B. Shergelashvili, N. S. Dzhalilov, S. Poedts","doi":"10.1063/5.0013490","DOIUrl":"https://doi.org/10.1063/5.0013490","url":null,"abstract":"We study the effects of heat flows and velocity shear on the parallel firehose instability in weakly collisional plasma flow. For this purpose we apply an anisotropic 16-moments MHD fluid closure model that takes into account the pressure and temperature anisotropy, as well as the effect of anisotropic heat flux. The linear stability analysis of the firehose modes is carried out in the incompressible limit, where the MHD flow is parallel to the background magnetic field, while the velocity is sheared in the direction transverse to the flow direction. It seems that an increase of the velocity shear parameter leads to higher growth rates of the firehose instability. The increase of the instability growth rate is most profound for perturbations with oblique wave-numbers $k_{perp}/k_{parallel} < 1$. The heat flux parameter introduces an asymmetry of the instability growth in the shear plane: perturbations with wave-vectors with a component in the direction of the velocity shear grow significantly stronger as compared to those with components in the opposite direction. We discuss the implications of the presented study on the observable features of the solar wind and possible measurements of local parameters of the solar wind based on the stability constraints set by the firehose instability.","PeriodicalId":8461,"journal":{"name":"arXiv: Plasma Physics","volume":"160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86212571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Space-filter techniques for quasi-neutral hybrid-kinetic models 准中性混合动力模型的空间过滤技术

arXiv: Plasma Physics Pub Date : 2020-05-06 DOI: 10.1063/5.0012924

S. Cerri, Enrico Camporeale

引用次数: 9

Flattening of the tokamak current profile by a fast magnetic reconnection with implications for the solar corona 快速磁重联使托卡马克电流剖面变平，对日冕的影响

arXiv: Plasma Physics Pub Date : 2020-05-05 DOI: 10.1063/5.0014107

A. Boozer

引用次数: 13

Effects of collisions on the generation and suppression of temperature anisotropies and the Weibel instability 碰撞对温度各向异性的产生和抑制及维贝尔不稳定性的影响

arXiv: Plasma Physics Pub Date : 2020-04-28 DOI: 10.1103/PHYSREVRESEARCH.2.033233

K. Schoeffler, L. Silva

引用次数: 3

The ion-acoustic instability of the inductively coupled plasma driven by the ponderomotive electron current formed in the skin layer 电感耦合等离子体在蒙皮层中形成的有源电子电流驱动下的离子声不稳定性

arXiv: Plasma Physics Pub Date : 2020-04-28 DOI: 10.1063/1.5144472

V. Mikhailenko, V. Mikhailenko, H. J. Lee

引用次数: 4

Dependence of the impurity transport on the dominant turbulent regime in ELM-y H-mode discharges on the DIII-D tokamak DIII-D托卡马克上ELM-y h模放电中杂质输运对主导湍流区的依赖

arXiv: Plasma Physics Pub Date : 2020-04-23 DOI: 10.1063/5.0010725

Tomáš Odstrčil, N. Howard, F. Sciortino, C. Chrystal, C. Holland, E. Hollmann, G. McKee, K. Thome, T. Wilks

{"title":"Dependence of the impurity transport on the dominant turbulent regime in ELM-y H-mode discharges on the DIII-D tokamak","authors":"Tomáš Odstrčil, N. Howard, F. Sciortino, C. Chrystal, C. Holland, E. Hollmann, G. McKee, K. Thome, T. Wilks","doi":"10.1063/5.0010725","DOIUrl":"https://doi.org/10.1063/5.0010725","url":null,"abstract":"Laser blow-off injections of aluminum and tungsten have been performed on the DIII-D tokamak to investigate the variation of impurity transport in a set of dedicated ion and electron heating scans with a fixed value of the external torque. The particle transport is quantified via the Bayesian inference method, which, constrained by a combination of a charge exchange recombination spectroscopy, soft X-ray measurements, and VUV spectroscopy provides a detailed uncertainty quantification of the transport coefficients. Contrasting discharge phases with a dominant electron and ion heating reveal a factor of 30 increase in midradius impurity diffusion and a 3-fold drop in the impurity confinement time when additional electron heating is applied. Further, the calculated stationary aluminum density profiles reverse from peaked in electron heated to hollow in the ion heated case, following a similar trend as electron and carbon density profiles. Comparable values of a core diffusion have been observed for W and Al ions, while differences in the propagation dynamics of these impurities are attributed to pedestal and edge transport. Modeling of the core transport with non-linear gyrokinetics code CGYRO [J. Candy and E. Belly J. Comput. Phys. 324,73 (2016)], significantly underpredicts the magnitude of the variation in Al transport. The experiment demonstrates a 3-times steeper increase of impurity diffusion with additional electron heat flux and 10-times lower diffusion in ion heated case than predicted by the modeling. However, the CGYRO model correctly predicts that the Al diffusion dramatically increases below the linear threshold for the transition from the ion temperature gradient (ITG) to trapped electron mode (TEM).","PeriodicalId":8461,"journal":{"name":"arXiv: Plasma Physics","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90564819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Necessary and sufficient conditions for quasisymmetry 准对称的充分必要条件

arXiv: Plasma Physics Pub Date : 2020-04-23 DOI: 10.1063/5.0008551

E. Rodríguez, P. Helander, Ashis Bhattacharjee

引用次数: 31

Trajectory of a flying plasma mirror traversing a target with density gradient 等离子体反射镜在密度梯度目标上的飞行轨迹

arXiv: Plasma Physics Pub Date : 2020-04-22 DOI: 10.1063/5.0012374

Pisin Chen, G. Mourou

引用次数: 16

Compton recoil effects in staging of laser wakefield accelerators 激光尾流场加速器的康普顿后坐力效应

arXiv: Plasma Physics Pub Date : 2020-04-15 DOI: 10.1103/PHYSREVACCELBEAMS.23.071602

M. Streeter, Z. Najmudin

引用次数: 0

Ion versus Electron Heating in Compressively Driven Astrophysical Gyrokinetic Turbulence 压缩驱动的天体物理回旋动力学湍流中的离子与电子加热

arXiv: Plasma Physics Pub Date : 2020-04-10 DOI: 10.1103/physrevx.10.041050

Y. Kawazura, A. Schekochihin, M. Barnes, J. TenBarge, Y. Tong, K. Klein, W. Dorland

{"title":"Ion versus Electron Heating in Compressively Driven Astrophysical Gyrokinetic Turbulence","authors":"Y. Kawazura, A. Schekochihin, M. Barnes, J. TenBarge, Y. Tong, K. Klein, W. Dorland","doi":"10.1103/physrevx.10.041050","DOIUrl":"https://doi.org/10.1103/physrevx.10.041050","url":null,"abstract":"The partition of irreversible heating between ions and electrons in compressively driven (but subsonic) collisionless turbulence is investigated by means of nonlinear gyrokinetic simulations. We derive a prescription for the ion-to-electron heating ratio $Q_{text{i}}/Q_{text{e}}$ as a function of the compressive-to-Alfvenic driving power ratio $P_{text{compr}}/P_{text{AW}}$, of the ratio of ion thermal pressure to magnetic pressure $beta_{text{i}}$, and of the ratio of ion-to-electron background temperatures $T_{text{i}}/T_{text{e}}$. It is shown that $Q_{text{i}}/Q_{text{e}}$ is an increasing function of $P_{text{compr}}/P_{text{AW}}$. When the compressive driving is sufficiently large, $Q_{text{i}}/Q_{text{e}}$ approaches $simeq P_{text{compr}}/P_{text{AW}}$. This indicates that, in turbulence with large compressive fluctuations, the partition of heating is decided at the injection scales, rather than at kinetic scales. Analysis of phase-space spectra shows that the energy transfer from inertial-range compressive fluctuations to sub-Larmor-scale kinetic Alfven waves is absent for both low and high $beta_{text{i}}$, meaning that the compressive driving is directly connected to the ion entropy fluctuations, which are converted into ion thermal energy. This result suggests that preferential electron heating is a very special case requiring low $beta_{text{i}}$ and no, or weak, compressive driving. Our heating prescription has wide-ranging applications, including to the solar wind and to hot accretion disks such as M87 and Sgr A*.","PeriodicalId":8461,"journal":{"name":"arXiv: Plasma Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79127702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13