Journal of Plasma Physics最新文献

{"title":"Self-organization in the avalanche, quench and dissipation of a molecular ultracold plasma","authors":"K.L. Marroquín, R. Wang, A. Allahverdian, N. Durand-Brousseau, S. Colombini, F. Kogel, J.S. Keller, T. Langen, E.R. Grant","doi":"10.1017/s0022377823001472","DOIUrl":"https://doi.org/10.1017/s0022377823001472","url":null,"abstract":"<p>Spontaneous avalanche to plasma begins in the core of an ellipsoidal Rydberg gas of nitric oxide. Ambipolar expansion of NO<span><span><span data-mathjax-type=\"texmath\"><span>$^+$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240117100917405-0570:S0022377823001472:S0022377823001472_inline1.png\"/></span></span> draws energy from avalanche-heated electrons. Then, cycles of long-range resonant electron transfer from Rydberg molecules to ions equalize their relative velocities. This sequence of steps gives rise to a remarkable mechanics of self-assembly, in which the kinetic energy of initially formed hot electrons and ions drives an observed separation of plasma volumes. These dynamics adiabatically sequester energy in a reservoir of mass transport, starting a process that anneals separating volumes to form an apparent glass of strongly coupled ions and electrons. Short-time electron spectroscopy provides experimental evidence for complete ionization. The long lifetime of this system, particularly its stability with respect to recombination and neutral dissociation, suggests that this transformation affords a robust state of arrested relaxation, far from thermal equilibrium. We see this most directly in the excitation spectrum of transitions to states in the initially selected Rydberg series, detected as the long-lived signal that survives a flight time of <span><span><span data-mathjax-type=\"texmath\"><span>$500 mathrm {mu }$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240117100917405-0570:S0022377823001472:S0022377823001472_inline2.png\"/></span></span>s to reach an imaging detector. The initial density of electrons produced by prompt Penning ionization, which varies with the selected initial principal quantum number and density of the Rydberg gas, determines a balance between the rising density of ions and the falling density of Rydberg molecules. This Penning-regulated ion-Rydberg molecule balance appears necessary as a critical factor in achieving the long ultracold plasma lifetime to produce spectral features detected after very long delays.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"8 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139481325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupling multi-fluid dynamics equipped with Landau closures to the particle-in-cell method","authors":"Rouven Lemmerz, Mohamad Shalaby, Timon Thomas, Christoph Pfrommer","doi":"10.1017/s0022377823001113","DOIUrl":"https://doi.org/10.1017/s0022377823001113","url":null,"abstract":"<p>The particle-in-cell (PIC) method is successfully used to study magnetized plasmas. However, this requires large computational costs and limits simulations to short physical run times and often to set-ups of less than three spatial dimensions. Traditionally, this is circumvented either via hybrid-PIC methods (adopting massless electrons) or via magneto-hydrodynamic-PIC methods (modelling the background plasma as a single charge-neutral magneto-hydrodynamical fluid). Because both methods preclude modelling important plasma-kinetic effects, we introduce a new fluid-PIC code that couples a fully explicit and charge-conserving multi-fluid solver to the PIC code SHARP through a current-coupling scheme and solve the full set of Maxwell's equations. This avoids simplifications typically adopted for Ohm's law and enables us to fully resolve the electron temporal and spatial scales while retaining the versatility of initializing any number of ion, electron or neutral species with arbitrary velocity distributions. The fluid solver includes closures emulating Landau damping so that we can account for this important kinetic process in our fluid species. Our fluid-PIC code is second-order accurate in space and time. The code is successfully validated against several test problems, including the stability and accuracy of shocks and the dispersion relation and damping rates of waves in unmagnetized and magnetized plasmas. It also matches growth rates and saturation levels of the gyro-scale and intermediate-scale instabilities driven by drifting charged particles in magnetized thermal background plasmas in comparison with linear theory and PIC simulations. This new fluid-SHARP code is specially designed for studying high-energy cosmic rays interacting with thermal plasmas over macroscopic time scales.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139481923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prospects for a high-field, compact break-even axisymmetric mirror (BEAM) and applications","authors":"C.B. Forest, J.K. Anderson, D. Endrizzi, J. Egedal, S. Frank, K. Furlong, M. Ialovega, J. Kirch, R.W. Harvey, B. Lindley, Yu.V. Petrov, J. Pizzo, T. Qian, K. Sanwalka, O. Schmitz, J. Wallace, D. Yakovlev, M. Yu","doi":"10.1017/s0022377823001290","DOIUrl":"https://doi.org/10.1017/s0022377823001290","url":null,"abstract":"<p>This paper explores the feasibility of a break-even-class mirror referred to as BEAM (break-even axisymmetric mirror): a neutral-beam-heated simple mirror capable of thermonuclear-grade parameters and <span><span><span data-mathjax-type=\"texmath\"><span>$Qsim 1$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240116115223397-0336:S0022377823001290:S0022377823001290_inline1.png\"/></span></span> conditions. Compared with earlier mirror experiments in the 1980s, BEAM would have: higher-energy neutral beams, a larger and denser plasma at higher magnetic field, both an edge and a core and capabilities to address both magnetohydrodynamic and kinetic stability of the simple mirror in higher-temperature plasmas. Axisymmetry and high-field magnets make this possible at a modest scale enabling a short development time and lower capital cost. Such a <span><span><span data-mathjax-type=\"texmath\"><span>$Qsim 1$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240116115223397-0336:S0022377823001290:S0022377823001290_inline2.png\"/></span></span> configuration will be useful as a fusion technology development platform, in which tritium handling, materials and blankets can be tested in a real fusion environment, and as a base for development of higher-<span><span><span data-mathjax-type=\"texmath\"><span>$Q$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240116115223397-0336:S0022377823001290:S0022377823001290_inline3.png\"/></span></span> mirrors.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"17 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139480994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electron cyclotron resonance during plasma initiation","authors":"C. Albert Johansson, Pavel Aleynikov","doi":"10.1017/s0022377823001423","DOIUrl":"https://doi.org/10.1017/s0022377823001423","url":null,"abstract":"<p>Electron-cyclotron resonance heating (ECRH) is the main heating mechanism in the Wendelstein 7-X (W7-X) stellarator. Although second-harmonic ECRH (X2) has been used routinely for plasma startup, startup at third harmonic (X3) is known to be much more difficult. In this work, we investigate the energy gain of particles during nonlinear wave–particle interaction for conditions relevant to second- and third-harmonic startups in W7-X. We take into account both the beam and the ambient magnetic field inhomogeneities. The latter is shown to significantly increase the mean energy gain resulting from a single wave–particle resonant interaction. In W7-X-like conditions, the improvement in maximum gained energy is up to 4 times the analogous uniform magnetic field case. However, this improvement is not enough to ensure X3 startup. The optimal magnetic field inhomogeneity length scale for average energy gain and start up in W7-X-like conditions is found to be in the range of <span><span><span data-mathjax-type=\"texmath\"><span>$1$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240112135018386-0980:S0022377823001423:S0022377823001423_inline2.png\"/></span></span> to <span><span><span data-mathjax-type=\"texmath\"><span>$3 {rm km}^{-1}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240112135018386-0980:S0022377823001423:S0022377823001423_inline3.png\"/></span></span>. A possibility of using multiple beams with neighbouring resonances is also considered. A considerable enhancement of the energy gain is demonstrated.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"12 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139471138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved numerical simulation model for nuclear reaction rate calculations in high-speed plasma collisions","authors":"Bo Zeng, Zijia Zhao, Xiaohu Yang, Shaowu Yang, Yanyun Ma","doi":"10.1017/s0022377822000794","DOIUrl":"https://doi.org/10.1017/s0022377822000794","url":null,"abstract":"<p>Beam–target reactions in fusion plasmas play an important role in both magnetic confinement fusion and inertial confinement fusion in the condition of low-density plasmas with high-velocity interactions. The traditional method for calculating beam–target reaction rate neglects the transport process of incident particles in inhomogeneous plasmas, leading to errors providing that the temperature and density in the transport path of incident particles vary obviously. An improved method considering the transport process is proposed in this paper to eliminate the deficiencies. Then the method is employed in high-speed plasma collision studies. When the initial plasma density and temperature are set to <span><span><span data-mathjax-type=\"texmath\"><span>$0.5,{rm g},{rm cm}^{-3}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240110160745098-0021:S0022377822000794:S0022377822000794_inline2.png\"/></span></span> and 100 eV, it is found that the beam–target reaction rate calculated by the traditional method is almost identical to that by our method if the collision velocity is less than 600 km s<span><span><span data-mathjax-type=\"texmath\"><span>$^{-1}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240110160745098-0021:S0022377822000794:S0022377822000794_inline3.png\"/></span></span>. However, the traditional method is not suitable for study as the collision velocity gets higher, inducing obvious differences, which can reach 70 % at 1000 km s<span><span><span data-mathjax-type=\"texmath\"><span>$^{-1}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240110160745098-0021:S0022377822000794:S0022377822000794_inline4.png\"/></span></span>. The improved method will make large corrections to evaluate the importance of the non-negligible beam–target reaction for inertial confinement fusion schemes with large implosion velocity such as double-cone ignition and impact ignition, in which the high-speed plasmas collide with each other to realize plasma ignition.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"13 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139423885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and construction of the near-earth space plasma simulation system of the Space Plasma Environment Research Facility","authors":"W. Ling, C. Jing, J. Wan, A. Mao, Q. Xiao, J. Guan, J. Cheng, C. Liu, P. E","doi":"10.1017/s0022377823001460","DOIUrl":"https://doi.org/10.1017/s0022377823001460","url":null,"abstract":"<p>Our earth is immersed in the near-earth space plasma environment, which plays a vital role in protecting our planet against the solar-wind impact and influencing space activities. It is significant to investigate the physical processes dominating the environment, for deepening our scientific understanding of it and improving the ability to forecast the space weather. As a crucial part of the National Major Scientific and Technological Infrastructure–Space Environment Simulation Research Infrastructure (SESRI) in Harbin, the Space Plasma Environment Research Facility (SPERF) builds a system to replicate the near-earth space plasma environment in the laboratory. The system aims to simulate the three-dimensional (3-D) structure and processes of the terrestrial magnetosphere for the first time in the world, providing a unique platform to reveal the physics of the 3-D asymmetric magnetic reconnection relevant to the earth's magnetopause, wave–particle interaction in the earth's radiation belt, particles’ dynamics during the geomagnetic storm, etc. The paper will present the engineering design and construction of the near-earth space plasma simulation system of the SPERF, with a focus on the critical technologies that have been resolved to achieve the scientific goals. Meanwhile, the possible physical issues that can be studied based on the apparatus are sketched briefly. The earth-based system is of great value in understanding the space plasma environment and supporting space exploration.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"25 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139420562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the role of numerical diffusivity in MHD simulations of global accretion disc dynamos","authors":"C.J. Nixon, C.C.T. Pringle, J.E. Pringle","doi":"10.1017/s002237782300140x","DOIUrl":"https://doi.org/10.1017/s002237782300140x","url":null,"abstract":"&lt;p&gt;Observations, mainly of outbursts in dwarf novae, imply that the anomalous viscosity in highly ionized accretion discs is magnetic in origin and requires that the plasma &lt;span&gt;&lt;span&gt;&lt;span data-mathjax-type=\"texmath\"&gt;&lt;span&gt;${beta sim 1}$&lt;/span&gt;&lt;/span&gt;&lt;img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240104165850964-0798:S002237782300140X:S002237782300140X_inline1.png\"/&gt;&lt;/span&gt;&lt;/span&gt;. Until now, most simulations of the magnetic dynamo in accretion discs have used a local approximation (known as the shearing box). While these simulations demonstrate the possibility of a self-sustaining dynamo, the magnetic activity generated in these models saturates at &lt;span&gt;&lt;span&gt;&lt;span data-mathjax-type=\"texmath\"&gt;&lt;span&gt;$beta gg 1$&lt;/span&gt;&lt;/span&gt;&lt;img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240104165850964-0798:S002237782300140X:S002237782300140X_inline2.png\"/&gt;&lt;/span&gt;&lt;/span&gt;. This long-standing discrepancy has previously been attributed to the local approximation itself. There have been recent attempts at simulating magnetic activity in global accretion discs with parameters relevant to the dwarf novae. These too find values of &lt;span&gt;&lt;span&gt;&lt;span data-mathjax-type=\"texmath\"&gt;&lt;span&gt;$beta gg 1$&lt;/span&gt;&lt;/span&gt;&lt;img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240104165850964-0798:S002237782300140X:S002237782300140X_inline3.png\"/&gt;&lt;/span&gt;&lt;/span&gt;. We speculate that the tension between these models and the observations may be caused by numerical magnetic diffusivity. As a pedagogical example, we present exact time-dependent solutions for the evolution of weak magnetic fields in an incompressible fluid subject to linear shear and magnetic diffusivity. We find that the maximum factor by which the initial magnetic energy can be increased depends on the magnetic Reynolds number as &lt;span&gt;&lt;span&gt;&lt;span data-mathjax-type=\"texmath\"&gt;&lt;span&gt;${mathcal {R}}_{m}^{2/3}$&lt;/span&gt;&lt;/span&gt;&lt;img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240104165850964-0798:S002237782300140X:S002237782300140X_inline4.png\"/&gt;&lt;/span&gt;&lt;/span&gt;. We estimate that current global numerical simulations of dwarf nova discs have numerical magnetic Reynolds numbers around six orders of magnitude less than the physical value found in dwarf nova discs of &lt;span&gt;&lt;span&gt;&lt;span data-mathjax-type=\"texmath\"&gt;&lt;span&gt;${mathcal {R}}_{m} sim 10^{10}$&lt;/span&gt;&lt;/span&gt;&lt;img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240104165850964-0798:S002237782300140X:S002237782300140X_inline5.png\"/&gt;&lt;/span&gt;&lt;/span&gt;. We suggest that, given the current limitations on computing power, expecting to be able to compute realistic dynamo action in observable accretion discs using numerical MHD is, for the","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"23 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139102663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proton and helium ions acceleration in near-critical density gas targets by short-pulse Ti:Sa PW-class laser","authors":"J.L. Henares, P. Puyuelo-Valdes, C. Salgado-López, J.I. Apiñaniz, P. Bradford, F. Consoli, D. de Luis, M. Ehret, F. Hannachi, R. Hernández-Martín, A. Huber, L. Lancia, M. Mackeviciute, A. Maitrallain, J.-R. Marquès, J.A. Pérez-Hernández, C. Santos, J.J. Santos, V. Stankevic, M. Tarisien, V. Tomkus, L. Volpe, G. Gatti","doi":"10.1017/s0022377823001332","DOIUrl":"https://doi.org/10.1017/s0022377823001332","url":null,"abstract":"<p>The ability to quickly refresh gas-jet targets without cycling the vacuum chamber makes them a promising candidate for laser-accelerated ion experiments at high repetition rate. Here we present results from the first high repetition rate ion acceleration experiment on the VEGA-3 PW-class laser at CLPU. A near-critical density gas-jet target was produced by forcing a 1000 bar H<span><span><span data-mathjax-type=\"texmath\"><span>$_2$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231227162729962-0649:S0022377823001332:S0022377823001332_inline1.png\"/></span></span> and He gas mix through bespoke supersonic shock nozzles. Proton energies up to 2 MeV were measured in the laser forward direction and 2.2 MeV transversally. He<span><span><span data-mathjax-type=\"texmath\"><span>$^{2+}$</span></span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20231227162729962-0649:S0022377823001332:S0022377823001332_inline2.png\"/></span></span> ions up to 5.8 MeV were also measured in the transverse direction. To help maintain a consistent gas density profile over many shots, nozzles were designed to produce a high-density shock at distances larger than 1 mm from the nozzle exit. We outline a procedure for optimizing the laser–gas interaction by translating the nozzle along the laser axis and using different nozzle materials. Several tens of laser interactions were performed with the same nozzle which demonstrates the potential usefulness of gas-jet targets as high repetition rate particle source.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139053358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Guiding centre motion for particles in a ponderomotive magnetostatic end plug","authors":"T. Rubin, J.M. Rax, N.J. Fisch","doi":"10.1017/s0022377823001307","DOIUrl":"https://doi.org/10.1017/s0022377823001307","url":null,"abstract":"<p>The Hamiltonian dynamics of a single particle in a rotating plasma column, interacting with an magnetic multipole is perturbatively solved for up to second order, using the method of Lie transformations. First, the exact Hamiltonian is expressed in terms of canonical action-angle variables, and then an approximate integrable Hamiltonian is introduced, using another set of actions and angles, which describe the centre of oscillation for the particle. The perturbation introduces an effective ponderomotive potential, which to leading order is positive. At the second order, the pseudopotential consists of a sum of terms of the Miller form, and can have either sign. Additionally, at second order, the ponderomotive interaction introduces a modification to the particle effective mass, when considering the motion along the column axis. It is found that particles can be axially confined by the ponderomotive potentials, but acquire radial excursions which scale as the confining potential. The radial excursions of the particle along its trajectory are investigated, and a condition for the minimal rotation frequency for which the particle remains radially confined is derived. Last, we comment on the changes to the aforementioned solution to the pseudopotentials and particle trajectory in the case of resonant motion, that is, a motion which has the same periodicity as the perturbation.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"70 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139053095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rotating Alfvén waves in rotating plasmas","authors":"J.-M. Rax, R. Gueroult, N.J. Fisch","doi":"10.1017/s0022377823001368","DOIUrl":"https://doi.org/10.1017/s0022377823001368","url":null,"abstract":"<p>Angular momentum coupling between a rotating magnetized plasma and torsional Alfvén waves carrying orbital angular momentum (OAM) is examined. It is demonstrated not only that rotation is the source of Fresnel–Faraday rotation – or orbital Faraday rotation effects – for OAM-carrying Alfvén waves, but also that angular momentum from an OAM-carrying Alfvén wave can be transferred to a rotating plasma through the inverse process. For the direct process, the transverse structure angular rotation frequency is derived by considering the dispersion relation for modes with opposite OAM content. For the inverse process, the torque exerted on the plasma is derived as a function of wave and plasma parameters.</p>","PeriodicalId":16846,"journal":{"name":"Journal of Plasma Physics","volume":"165 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139053359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}