Physics of Plasmas最新文献_第7页

Artificial excitation and propagation of ultra-low frequency signals in the polar ionosphere 极地电离层中超低频率信号的人工激发和传播

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-19 DOI: 10.1063/5.0202317

Yong Li, Hui Li, Jian Wu, Xingbao Lyu, Yan Chai, Chengxun Yuan, Zhongxiang Zhou

{"title":"Artificial excitation and propagation of ultra-low frequency signals in the polar ionosphere","authors":"Yong Li, Hui Li, Jian Wu, Xingbao Lyu, Yan Chai, Chengxun Yuan, Zhongxiang Zhou","doi":"10.1063/5.0202317","DOIUrl":"https://doi.org/10.1063/5.0202317","url":null,"abstract":"This paper has established a relatively comprehensive model for ultra-low frequency (ULF) current induced by thermal pressure gradients and its propagation. In the ULF current excitation model, we decomposed the current into a constant term unaffected by altitude and a product with a function significantly influenced by altitude. Combining this with the EISCAT background, we determined that for modulation frequencies below 5 Hz, the optimal height for ULF current excitation corresponds to the critical frequency height. We calculated the ionospheric currents at heating altitudes of 332 km for modulation frequencies of 5 Hz; the corresponding maximum currents were 1.03 × 10−10 A·m−2. By incorporating the current into the ULF waves propagation model based on magnetoionic theory, we found that the electromagnetic field energy is mainly concentrated in the horizontal direction, indicating that the energy primarily propagates outward through magnetosonic waves. The dominant components are the electric field component Ey and the magnetic field component Bz, whose maximum values reached 1.1 μV·m−1 and 1.5 pT. Unfortunately, magnetosonic waves cannot propagate downward due to the sharp variation in the real part of the refractive index between 200 and 300 km. However, the shear Alfvén waves component By can propagate downward, and there is still an intensity of approximately 0.1 pT at the bottom of the ionosphere, which is because the refractive index of shear Alfvén waves is most uniform in the parallel magnetic field direction, allowing By to propagate parallel to the magnetic field effectively.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"34 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221905","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}

引用次数: 0

Efficient laser-driven proton acceleration from a petawatt contrast-enhanced second harmonic mixed-glass laser system 兆瓦级对比度增强型二次谐波混合玻璃激光系统的高效激光驱动质子加速度

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-19 DOI: 10.1063/5.0191366

B. Gonzalez-Izquierdo, P. Fischer, M. Touati, J. Hartmann, M. Speicher, V. Scutelnic, D. E. Rivas, G. Bodini, A. Fazzini, M. M. Günther, A. K. Härle, K. Kenney, E. Schork, S. Bruce, M. Spinks, H. J. Quevedo, A. Helal, M. Medina, E. Gaul, H. Ruhl, M. Schollmeier, S. Steinke, G. Korn

{"title":"Efficient laser-driven proton acceleration from a petawatt contrast-enhanced second harmonic mixed-glass laser system","authors":"B. Gonzalez-Izquierdo, P. Fischer, M. Touati, J. Hartmann, M. Speicher, V. Scutelnic, D. E. Rivas, G. Bodini, A. Fazzini, M. M. Günther, A. K. Härle, K. Kenney, E. Schork, S. Bruce, M. Spinks, H. J. Quevedo, A. Helal, M. Medina, E. Gaul, H. Ruhl, M. Schollmeier, S. Steinke, G. Korn","doi":"10.1063/5.0191366","DOIUrl":"https://doi.org/10.1063/5.0191366","url":null,"abstract":"Efficient laser-driven plasma acceleration of ion beams requires precision control of the target–plasma profile, which is crucial to optimize the laser energy transfer. Along the laser propagation direction, this can be achieved by tailoring the temporal structure of the laser pulse. We show for the first time that frequency-doubling of a short pulse (hundreds-femtosecond range) petawatt-class mixed-glass laser system, which results in temporal intensity contrast enhancement, enables surface and volumetric laser–energy coupling, and the acceleration of proton beams from few-nanometer-thick foil targets. Experimentally, maximum ion energies and laser-to-proton energy conversion efficiencies were found to be both maximized at optimum laser and target conditions manifested when the normalized target density nearly equalizes the normalized laser vector potential, which is in agreement with theory and simulations. These signatures are recognized as a unique indication of the interaction between ultra-intense laser pulses with high temporal intensity contrast and ultra-thin nanometer-scale targets. Transverse modulations of accelerated proton beams in the form of bubble- and ring-like structures measured in the thinnest targets provide additional evidence of volumetric laser-driven particle acceleration regimes and transitional features in ultra-thin foil targets specific to laser–plasma interactions characterized by a high temporal intensity contrast. These results open avenues in the generation of high contrast laser pulses from short-pulse-femtosecond petawatt mixed-glass laser systems and demonstrate the feasibility of this technique for applications requiring high laser intensity contrast with high efficiency.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"26 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227584","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}

引用次数: 0

Azimuthal ion dynamics at the inner pole of an axisymmetric Hall thruster 轴对称霍尔推进器内极的方位离子动力学

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-19 DOI: 10.1063/5.0214477

Parker J. Roberts, Vernon H. Chaplin, Benjamin A. Jorns

{"title":"Azimuthal ion dynamics at the inner pole of an axisymmetric Hall thruster","authors":"Parker J. Roberts, Vernon H. Chaplin, Benjamin A. Jorns","doi":"10.1063/5.0214477","DOIUrl":"https://doi.org/10.1063/5.0214477","url":null,"abstract":"The azimuthal dynamics of ions along the inner pole of a Hall thruster with a centrally mounted cathode and a magnetic shielding topography are experimentally investigated. A time-averaged laser-induced fluorescence diagnostic is implemented to characterize the azimuthal ion velocity distribution, and its moments are computed numerically to infer bulk rotation speed and ion temperature. It is found that the time-averaged ion swirl velocity grows to 2 km/s in the near-pole region, and the cathode ions exhibit ion temperatures in the azimuthal direction approaching 8 eV. Both of these quantities exceed the speeds and temperatures anticipated from classical acceleration and heating. Time-resolved laser-induced fluorescence is then employed to investigate the role of plasma fluctuations in driving the time-averaged ion properties. Semicoherent fluctuations at 90 kHz are observed in the ion velocity distribution and its associated moments. These oscillations are correlated with the gradient-driven anti-drift wave, which propagates azimuthally in the near-field cathode plume. Quasilinear theory is used to construct a 1D model for acceleration and heating of the ion population as a result of the anti-drift mode. This approach demonstrates qualitative agreement with the time-averaged ion velocity and temperature, suggesting that the anti-drift mode may be a dominant driver of azimuthal ion acceleration and heating in front of the cathode keeper and the inner half of the inner front pole cover. These results are discussed in terms of their relevance to the erosion of thruster surfaces in the near-field cathode plume.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"38 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221904","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}

引用次数: 0

External static electric field assisted THz radiation generation via optical rectification of secant hyperbolic laser pulse in a plasma 通过等离子体中秒双曲激光脉冲的光学整流产生外部静电场辅助太赫兹辐射

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-16 DOI: 10.1063/5.0223433

Vivek Kumar Shukla, Monika Singh, Saba Hussain, Ram Kishor Singh

引用次数: 0

Depth-resolved deuterium retention analysis in displacement-damaged tungsten using laser-induced breakdown spectroscopy 利用激光诱导击穿光谱对位移损伤钨中的氘保留进行深度分辨分析

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-15 DOI: 10.1063/5.0211493

E. Wüst, T. Schwarz-Selinger, C. Kawan, L. Gao, S. Brezinsek

{"title":"Depth-resolved deuterium retention analysis in displacement-damaged tungsten using laser-induced breakdown spectroscopy","authors":"E. Wüst, T. Schwarz-Selinger, C. Kawan, L. Gao, S. Brezinsek","doi":"10.1063/5.0211493","DOIUrl":"https://doi.org/10.1063/5.0211493","url":null,"abstract":"Fuel retention in plasma-facing components (PFCs) is a critical issue in future nuclear fusion reactors operating with Deuterium-Tritium (DT) regarding nuclear safety and fulfillment of the T cycle. However, during DT plasma operation, highly energetic neutrons will induce damage in the lattice of W PFCs causing enhanced fuel retention in defects or traps. Laser-Induced Breakdown Spectroscopy (LIBS) is a potential tool to monitor the T-content in situ in PFCs of future nuclear fusion devices. This article presents an ex situ study on pre-damaged W material after D plasma exposure to qualify the method and mimic conditions expected in a reactor. ITER grade W samples were displacement-damaged by 10.8 MeV W ions to a damage dose of 0.23 dpa and exposed to low temperature deuterium plasma at low energy in PlaQ. The resulting deuterium concentration was analyzed by using 3He Nuclear Reaction Analysis (depth resolution of ≈150 nm) as a well-established method, and LIBS (picosecond laser pulses, depth resolution of 15 nm). The sample with the highest deuterium concentration showed a deuterium-rich zone up to a depth of 1.13 μm using both techniques. This is close to the expected W ion-induced damage depth of ≈1 μm. The results imply that LIBS as an in situ technique for tritium monitoring could be a viable option for a reactor.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"62 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221907","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}

引用次数: 0

The crucial role of diagnostics in achieving ignition on the National Ignition Facility (NIF) 诊断在实现国家点火装置（NIF）点火方面的关键作用

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-14 DOI: 10.1063/5.0211684

J. D. Kilkenny, A. Pak, O. L. Landen, A. S. Moore, N. B. Meezan, S. W. Haan, W. W. Hsing, S. H. Batha, D. K. Bradley, M. Gatu-Johnson, A. J. Mackinnon, S. P. Regan, V. A. Smalyuk

{"title":"The crucial role of diagnostics in achieving ignition on the National Ignition Facility (NIF)","authors":"J. D. Kilkenny, A. Pak, O. L. Landen, A. S. Moore, N. B. Meezan, S. W. Haan, W. W. Hsing, S. H. Batha, D. K. Bradley, M. Gatu-Johnson, A. J. Mackinnon, S. P. Regan, V. A. Smalyuk","doi":"10.1063/5.0211684","DOIUrl":"https://doi.org/10.1063/5.0211684","url":null,"abstract":"Well over 100 diagnostics can operate on the National Ignition Facility (NIF) as a result of several decades of development on NIF, and before that on Nova, OMEGA, and earlier LLNL lasers. A subset of these have guided the approach to achieving ignition on the NIF in 2022 [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129(7), 075001 (2022)]. Achieving ignition on NIF has required many types of experiments with this core set of diagnostics, some constraining known unknowns and some revealing surprises—arguably unknown unknowns. Early design work realized that the extreme precision required for ignition on NIF would require fine-tuning by experiment, that is, measuring and adjusting known unknowns. Many examples are given where the use of the core set of ignition diagnostics in experimental arrangements called platforms demonstrated control of the key theoretical parameters defined as shape, adiabat, velocity, and mix. The direction of the adjustments to input conditions is found either by trend analysis or, in many cases, by observing from the diagnostic data the direction to make an adjustment. In addition, diagnostics have revealed some unexpected or neglected known issues, which degrade performance, or unexpected issues, unknown unknowns. Some of these factors had been previously considered, but underestimated or difficult to calculate at the time. The overall methodology can be described as a variant of Popper's falsifiability philosophy [K. Popper, The Logic of Scientific Discovery (Hutchinson, 1974)]. This paper summarizes the role of ignition diagnostics in terms of falsification or validation of theory or experimental setup as well as uncovering unexpected issues. The journey to ignition started in the seventies with a 1-µm wavelength laser producing disastrous results. Diagnostics have guided us to the recent multi-decadal goal of demonstrating ignition and burn in the laboratory.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"39 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221908","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}

引用次数: 0

Numerical dissipation induced by the low-pass filtering in nonlinear gyrokinetic simulations 非线性陀螺动力学模拟中的低通滤波引起的数值耗散

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-14 DOI: 10.1063/5.0222980

Zihao Wang, Shaojie Wang

引用次数: 0

Experimental investigation of an electronegative cylindrical capacitively coupled geometrically asymmetric plasma discharge with an axisymmetric magnetic field 带轴对称磁场的负电圆柱形电容耦合几何不对称等离子体放电的实验研究

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-13 DOI: 10.1063/5.0208653

Swati Dahiya, Narayan Sharma, Shivani Geete, Sarveshwar Sharma, Nishant Sirse, Shantanu Karkari

{"title":"Experimental investigation of an electronegative cylindrical capacitively coupled geometrically asymmetric plasma discharge with an axisymmetric magnetic field","authors":"Swati Dahiya, Narayan Sharma, Shivani Geete, Sarveshwar Sharma, Nishant Sirse, Shantanu Karkari","doi":"10.1063/5.0208653","DOIUrl":"https://doi.org/10.1063/5.0208653","url":null,"abstract":"In this study, we have investigated the production of negative ions by mixing electronegative oxygen gas with electropositive argon gas in a geometrically asymmetric cylindrical capacitively coupled radio frequency plasma discharge. The plasma parameters such as density (electron, positive, and negative ion), negative ion fraction, and electron temperature are investigated for fixed gas pressure and increasing axial magnetic field strength. The axisymmetric magnetic field creates an E × B drift in the azimuthal direction, leading to the confinement of high-energy electrons at the radial edge of the chamber, resulting in decreased species density and negative ion fraction in the plasma bulk. However, the electron temperature increases with the magnetic field. It is concluded that low magnetic fields are better suited for negative ion production in such devices. Furthermore, in addition to the percentage ratio of the two gases, the applied axial magnetic field also plays a vital role in controlling negative ion fraction.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"60 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221930","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}

引用次数: 0

Investigating nonlinear magnetohydrodynamics in an optimized, reactor-scale quasi-axisymmetric stellarator 研究优化的反应堆级准轴对称恒星器中的非线性磁流体力学

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-13 DOI: 10.1063/5.0215594

A. M. Wright, N. M. Ferraro

{"title":"Investigating nonlinear magnetohydrodynamics in an optimized, reactor-scale quasi-axisymmetric stellarator","authors":"A. M. Wright, N. M. Ferraro","doi":"10.1063/5.0215594","DOIUrl":"https://doi.org/10.1063/5.0215594","url":null,"abstract":"We use the new simulation capabilities of the extended-magnetohydrodynamic (MHD) code, M3D-C1, to investigate the nonlinear MHD properties of a reactor-scale quasisymmetric stellarator equilibrium. Our model captures the self-consistent evolution of the magnetic field, temperature, density, and flow profiles without imposing restrictions on the structure of the first. We include the effects of resistivity using a realistic temperature-dependent Spitzer model, along with a model for heat transport that captures the key physical characteristic, namely, strongly anisotropic diffusion in directions perpendicular and parallel to the magnetic field. We consider a quasi-axisymmetric, finite-pressure equilibrium that was optimized for self-consistent bootstrap current, quasi-symmetry, and energetic particle confinement. Our assessment finds that the equilibrium is highly unstable to interchange-like pressure-driven instabilities near the plasma edge. The initially unstable modes rapidly destabilize other modes in the direction of the N-fold rotational symmetry (toroidal, in this case). For this equilibrium, N = 2, meaning destabilization of a large number of even-numbered toroidal Fourier modes. Thus, field-periodicity is likely to be an important factor in the nonlinear MHD stability characteristics of optimized stellarators.","PeriodicalId":20175,"journal":{"name":"Physics of Plasmas","volume":"40 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142221909","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}

引用次数: 0

Magnetic reconnection on a Klein bottle 克莱因瓶上的磁重联

IF 2.2 3区物理与天体物理

Physics of Plasmas Pub Date : 2024-08-13 DOI: 10.1063/5.0222454

Luke Xia, M. Swisdak

引用次数: 0