1
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Vincent SPH, Guittienne P, Quigley P, Sepulchre C, Jacquier R, Bertizzolo R, Baquero-Ruiz M, Howling AA, Furno I. A birdcage resonant antenna for helicon wave generation in TORPEX. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:093505. [PMID: 39225574 DOI: 10.1063/5.0212529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/30/2024] [Indexed: 09/04/2024]
Abstract
A birdcage resonant helicon antenna is designed, mounted, and tested in the toroidal device TORPEX. The birdcage resonant antenna is an alternative to the usual Boswell or half-helical antenna designs commonly used for ∼10 cm diameter helicon sources in low temperature plasma devices. The main advantage of the birdcage antenna lies in its resonant nature, which makes it easily operational even at large scales, an appealing feature for the TORPEX device whose poloidal cross section is 40 cm in diameter. With this antenna, helicon waves are shown to be launched and sustained throughout the whole torus of TORPEX. The helicon waves can be launched at low power on a pre-existing magnetron-generated plasma with little effect on the density profiles. The birdcage antenna can also be used alone to produce plasma, which removes the constraint of a narrow range of applied magnetic fields required by the magnetron, opening the way to a new range of studies on TORPEX with the external magnetic field as a control parameter.
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Affiliation(s)
- Simon P H Vincent
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Philippe Guittienne
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Patrick Quigley
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Cyrille Sepulchre
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Rémy Jacquier
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Robert Bertizzolo
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Marcelo Baquero-Ruiz
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Alan A Howling
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Ivo Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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2
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Qayyum A, Naseer MU, Deeba F, Ahmad S, Shah SIW, Imran M, Hussain S, Zakaullah M. Swept Langmuir probe investigation of a time varying DC discharge. SN APPLIED SCIENCES 2021. [DOI: 10.1007/s42452-020-04019-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AbstractThe paper reports on the development and application of a swept Langmuir probe to characterize plasma between two disc-like electrodes. A battery was added to a probe circuit to offset against the cathode fall voltage, and to make the sweep voltage effective at the probe tip. This arrangement allowed the collection of the electron and ion parts of the probe current and the subsequent construction of time-resolved current–voltage IP(V) characteristics with a time resolution of about one millisecond. The probe collected electron current in the lower voltage region of the discharge waveform where it surmounted the cathode fall voltage, whereas the ion current was collected continuously due to an accelerating field for the ions. The results highlighted how the cathode fall voltage limits the collection of the electron and ion parts of the probe current and how to handle the problem with a series battery in the probe circuit. In addition to the swept single-probe, a triple-probe was used simultaneously to compare and validate the results.
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3
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Mirzaei H, Amrollahi R, Ghasemi M. Optimizing the Plasma startup through ECR plasma pre-ionization in Taban Tokamak via Triple Langmuir probe. FUSION ENGINEERING AND DESIGN 2020. [DOI: 10.1016/j.fusengdes.2019.111362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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4
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Manke F, Baquero-Ruiz M, Furno I, Chellaï O, Fasoli A, Ricci P. Truncated Lévy motion through path integrals and applications to nondiffusive suprathermal ion transport. Phys Rev E 2019; 100:052122. [PMID: 31869979 DOI: 10.1103/physreve.100.052122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Indexed: 11/07/2022]
Abstract
Fractional Levy motion has been derived from its generalized Langevin equation via path integrals in earlier works and has since proven to be a useful model for nonlocal and non-Markovian processes, especially in the context of nondiffusive transport. Here, we generalize the approach to treat tempered Lévy distributions and derive the propagator and diffusion equation of truncated asymmetrical fractional Levy motion via path integrals. The model now recovers exponentially tempered tails above a chosen scale in the propagator, and therefore finite moments at all orders. Concise analytical expressions for its variance, skewness, and kurtosis are derived as a function of time. We then illustrate the versatility of this model by applying it to simulations of the turbulent transport of fast ions in the TORPEX basic plasma device.
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Affiliation(s)
- F Manke
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - M Baquero-Ruiz
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - I Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Chellaï
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - A Fasoli
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - P Ricci
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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5
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Février O, Theiler C, De Oliveira H, Labit B, Fedorczak N, Baillod A. Analysis of wall-embedded Langmuir probe signals in different conditions on the Tokamak à Configuration Variable. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:053502. [PMID: 29864827 DOI: 10.1063/1.5022459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper presents the current wall-embedded Langmuir probe system installed on the Tokamak à Configuration Variable (TCV), as well as the analysis tool chain used to interpret the current-voltage characteristic obtained when the probes are operated in swept-bias conditions. The analysis is based on a four-parameter fit combined with a minimum temperature approach. In order to reduce the effect of plasma fluctuations and measurement noise, several current-voltage characteristics are usually averaged before proceeding to the fitting. The impact of this procedure on the results is investigated, as well as the possible role of finite resistances in the circuitry, which could lead to an overestimation of the temperature. We study the application of the procedure in a specific regime, the plasma detachment, where results from other diagnostics indicate that the electron temperature derived from the Langmuir probes might be overestimated. To address this issue, we explore other fitting models and, in particular, an extension of the asymmetric double probe fit, which features effects of sheath expansion. We show that these models yield lower temperatures (up to approximately 60%) than the standard analysis in detached conditions, particularly for a temperature peak observed near the plasma strike point, but a discrepancy with other measurements remains. We explore a possible explanation for this observation, the presence of a fast electron population, and assess how robust the different methods are in such conditions.
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Affiliation(s)
- O Février
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - C Theiler
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - H De Oliveira
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - B Labit
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - N Fedorczak
- CEA, IRFM, F-13108 Saint Paul-lez-Durance, France
| | - A Baillod
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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6
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Chellaï O, Alberti S, Baquero-Ruiz M, Furno I, Goodman T, Manke F, Plyushchev G, Guidi L, Koehn A, Maj O, Poli E, Hizanidis K, Figini L, Ricci D. Millimeter-Wave Beam Scattering by Field-Aligned Blobs in Simple Magnetized Toroidal Plasmas. PHYSICAL REVIEW LETTERS 2018; 120:105001. [PMID: 29570337 DOI: 10.1103/physrevlett.120.105001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Indexed: 06/08/2023]
Abstract
The first direct experimental measurements of the scattering of a millimeter-wave beam by plasma blobs in a simple magnetized torus are reported. The wavelength of the beam is comparable to the characteristic size of the blob. In situ Langmuir probe measurements show that fluctuations of the electron density induce correlated fluctuations of the transmitted power. A first-principles full-wave model, using conditionally sampled 2D electron density profiles, predicts fluctuations of the millimeter-wave power that are in agreement with experiments.
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Affiliation(s)
- O Chellaï
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - S Alberti
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - M Baquero-Ruiz
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - I Furno
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - T Goodman
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - F Manke
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - G Plyushchev
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - L Guidi
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - A Koehn
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
- Institute of Interfacial Process Engineering and Plasma Technology, University of Stuttgart, 70174 Stuttgart, Germany
| | - O Maj
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - E Poli
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - K Hizanidis
- National Technical University of Athens, 106 82 Athens, Greece
| | - L Figini
- Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, 20125 Milan, Italy
| | - D Ricci
- Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, 20125 Milan, Italy
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7
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Tsui CK, Boedo JA, Stangeby PC. Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:013505. [PMID: 29390679 DOI: 10.1063/1.4995353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter lp, and the model is thus referred to as the "perimeter sheath expansion method." lp is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ∼ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ∼ 0 and for V = Vf.
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Affiliation(s)
- C K Tsui
- University of California-San Diego, La Jolla, California 92093, USA
| | - J A Boedo
- University of California-San Diego, La Jolla, California 92093, USA
| | - P C Stangeby
- University of Toronto Institute for Aerospace Studies, Toronto, Ontario M3H 5T6, Canada
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8
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Baquero-Ruiz M, Avino F, Chellai O, Fasoli A, Furno I, Jacquier R, Manke F, Patrick S. Dual Langmuir-probe array for 3D plasma studies in TORPEX. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:113504. [PMID: 27910384 DOI: 10.1063/1.4968024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/06/2016] [Indexed: 06/06/2023]
Abstract
We have designed and installed a new Langmuir-probe (LP) array diagnostic to determine basic three-dimensional (3D) features of plasmas in TORPEX. The diagnostic consists of two identical LP arrays, placed on opposite sides of the apparatus, which provide comprehensive coverage of the poloidal cross section at the two different toroidal locations. Cross correlation studies of signals from the arrays provide a basic way to extract 3D information from the plasmas, as experiments show. Moreover, the remarkable signal-to-noise performance of the front-end electronics allows us to follow a different approach in which we combine information from all probes in both arrays to reconstruct elementary 3D plasma structures at each acquisition time step. Then, through data analysis, we track the structures as they evolve in time. The LP arrays include a linear-motion mechanism that can displace radially the probes located on the low field side for experiments that require fine-tuning of the probe locations, and for operational compatibility with the recently installed in-vessel toroidal conductor.
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Affiliation(s)
- M Baquero-Ruiz
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - F Avino
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - O Chellai
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A Fasoli
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - I Furno
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - R Jacquier
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - F Manke
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - S Patrick
- Swiss Plasma Center (SPC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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9
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Sheftman D, Gupta D, Roche T, Thompson MC, Giammanco F, Conti F, Marsili P, Moreno CD. Jet outflow and open field line measurements on the C-2U advanced beam-driven field-reversed configuration plasma experiment. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11D432. [PMID: 27910352 DOI: 10.1063/1.4960059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Knowledge and control of the axial outflow of plasma particles and energy along open-magnetic-field lines are of crucial importance to the stability and longevity of the advanced beam-driven field-reversed configuration plasma. An overview of the diagnostic methods used to perform measurements on the open field line plasma on C-2U is presented, including passive Doppler impurity spectroscopy, microwave interferometry, and triple Langmuir probe measurements. Results of these measurements provide the jet ion temperature and axial velocity, electron density, and high frequency density fluctuations.
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Affiliation(s)
- D Sheftman
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688-7010, USA
| | - D Gupta
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688-7010, USA
| | - T Roche
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688-7010, USA
| | - M C Thompson
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688-7010, USA
| | - F Giammanco
- Department of Physics, University of Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
| | - F Conti
- Department of Physics, University of Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
| | - P Marsili
- Department of Physics, University of Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
| | - C D Moreno
- Department of Physics, University of Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
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10
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Liu Y, Zhang Z, Lei J, Cao J, Yu P, Zhang X, Xu L, Zhao Y. Design and construction of Keda Space Plasma Experiment (KSPEX) for the investigation of the boundary layer processes of ionospheric depletions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:093504. [PMID: 27782598 DOI: 10.1063/1.4962406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this work, the design and construction of the Keda Space Plasma EXperiment (KSPEX), which aims to study the boundary layer processes of ionospheric depletions, are described in detail. The device is composed of three stainless-steel sections: two source chambers at both ends and an experimental chamber in the center. KSPEX is a steady state experimental device, in which hot filament arrays are used to produce plasmas in the two sources. A Macor-mesh design is adopted to adjust the plasma density and potential difference between the two plasmas, which creates a boundary layer with a controllable electron density gradient and inhomogeneous radial electric field. In addition, attachment chemicals can be released into the plasmas through a tailor-made needle valve which leads to the generation of negative ions plasmas. Ionospheric depletions can be modeled and simulated using KSPEX, and many micro-physical processes of the formation and evolution of an ionospheric depletion can be experimentally studied.
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Affiliation(s)
- Yu Liu
- CAS Key Laboratory of Geospace Environment, School of Earth and Space Science, University of Science and Technology of China, Hefei 230026, China
| | - Zhongkai Zhang
- CAS Key Laboratory of Geospace Environment, Modern Physics Department, University of Science and Technology of China, Hefei 230026, China
| | - Jiuhou Lei
- CAS Key Laboratory of Geospace Environment, School of Earth and Space Science, University of Science and Technology of China, Hefei 230026, China
| | - Jinxiang Cao
- CAS Key Laboratory of Geospace Environment, Modern Physics Department, University of Science and Technology of China, Hefei 230026, China
| | - Pengcheng Yu
- CAS Key Laboratory of Geospace Environment, Modern Physics Department, University of Science and Technology of China, Hefei 230026, China
| | - Xiao Zhang
- CAS Key Laboratory of Geospace Environment, Modern Physics Department, University of Science and Technology of China, Hefei 230026, China
| | - Liang Xu
- CAS Key Laboratory of Geospace Environment, Modern Physics Department, University of Science and Technology of China, Hefei 230026, China
| | - Yaodong Zhao
- CAS Key Laboratory of Geospace Environment, Modern Physics Department, University of Science and Technology of China, Hefei 230026, China
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11
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Qayyum A, Ahmad S, Khan R, Hussain S, Deeba F, Javed MA, Ahmed N, Ali R, Mehmood S. Triple-probe Diagnostic Measurements in Plasma of GLAST Spherical Tokamak. JOURNAL OF FUSION ENERGY 2015. [DOI: 10.1007/s10894-015-0010-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Bovet A, Fasoli A, Ricci P, Furno I, Gustafson K. Nondiffusive transport regimes for suprathermal ions in turbulent plasmas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:041101. [PMID: 25974432 DOI: 10.1103/physreve.91.041101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Indexed: 06/04/2023]
Abstract
The understanding of the transport of suprathermal ions in the presence of turbulence is important for fusion plasmas in the burning regime that will characterize reactors, and for space plasmas to understand the physics of particle acceleration. Here, three-dimensional measurements of a suprathermal ion beam in the toroidal plasma device TORPEX are presented. These measurements demonstrate, in a turbulent plasma, the existence of subdiffusive and superdiffusive transport of suprathermal ions, depending on their energy. This result stems from the unprecedented combination of uniquely resolved measurements and first-principles numerical simulations that reveal the mechanisms responsible for the nondiffusive transport. The transport regime is determined by the interaction of the suprathermal ion orbits with the turbulent plasma dynamics, and is strongly affected by the ratio of the suprathermal ion energy to the background plasma temperature.
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Affiliation(s)
- A Bovet
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
| | - A Fasoli
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
| | - P Ricci
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
| | - I Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
| | - K Gustafson
- École Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Computational Systems Biology, Institute of Bioengineering, School of Life Sciences, CH-1015 Lausanne, Switzerland
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13
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Bovet A, Fasoli A, Furno I. Time-Resolved Measurements of Suprathermal Ion Transport Induced by Intermittent Plasma Blob Filaments. PHYSICAL REVIEW LETTERS 2014; 113:225001. [PMID: 25494075 DOI: 10.1103/physrevlett.113.225001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Indexed: 06/04/2023]
Abstract
Suprathermal ion turbulent transport in magnetized plasmas is generally nondiffusive, ranging from subdiffusive to superdiffusive depending on the interplay of the turbulent structures and the suprathermal ion orbits. Here, we present time-resolved measurements of the cross-field suprathermal ion transport in a toroidal magnetized turbulent plasma. Measurements in the superdiffusive regime are characterized by a higher intermittency than in the subdiffusive regime. Using conditional averaging, we show that, when the transport is superdiffusive, suprathermal ions are transported by intermittent field-elongated turbulent structures that are radially propagating.
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Affiliation(s)
- A Bovet
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
| | - A Fasoli
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
| | - I Furno
- École Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne, Switzerland
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14
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Triple Probe Measurements in Transient Plasma of Pulsed Capacitive Discharge. JOURNAL OF FUSION ENERGY 2014. [DOI: 10.1007/s10894-014-9815-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Bousselin G, Lemoine N, Cavalier J, Heuraux S, Bonhomme G. Note: On the measurement of plasma potential fluctuations using emissive probes. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:056102. [PMID: 24880427 DOI: 10.1063/1.4875585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this Note, it is pointed out that emissive probes cannot be used to directly and reliably measure plasma potential fluctuations. An experimentally validated model demonstrates indeed that the floating potential fluctuations of an emissive probe which floats at the mean plasma potential depend not only on the plasma potential fluctuations but also on electron density and temperature fluctuations.
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Affiliation(s)
- G Bousselin
- IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre, France
| | - N Lemoine
- IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre, France
| | - J Cavalier
- IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre, France
| | - S Heuraux
- IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre, France
| | - G Bonhomme
- IJL, Université de Lorraine, CNRS (UMR 7198), 54506 Vandoeuvre, France
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16
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Qayyum A, Ahmad N, Ahmad S, Deeba F, Ali R, Hussain S. Time-resolved measurement of plasma parameters by means of triple probe. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:123502. [PMID: 24387429 DOI: 10.1063/1.4838658] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Triple Langmuir probe (TLP) diagnostic system with its necessary driving circuit is developed and successfully applies for time-resolved measurement of plasma parameters in the negative glow region of pulsating-dc discharge. This technique allows the instantaneous measurement of electron temperature [T_], electron number density [n_] as well as plasma fluctuations without any voltage or frequency sweep. In TLP configuration two probes are differentially biased and serve as a floating symmetric double probe whereas the third probe is simply floating into plasma to measure floating potential as a function of time and thus incorporates the effect of plasma fluctuations. As an example of the application to time-dependent plasmas, basic plasma parameters such as floating potential, electron temperature, and electron number density in low pressure air discharge are determined as a function of time for different fill pressure. The results demonstrate temporal evolution of plasma parameters and thus plasma generation progression for different fill pressures.
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Affiliation(s)
- A Qayyum
- National Tokamak Fusion Program, 3329 Islamabad, Pakistan
| | - N Ahmad
- National Tokamak Fusion Program, 3329 Islamabad, Pakistan
| | - S Ahmad
- National Tokamak Fusion Program, 3329 Islamabad, Pakistan
| | - Farah Deeba
- National Tokamak Fusion Program, 3329 Islamabad, Pakistan
| | - Rafaqat Ali
- National Tokamak Fusion Program, 3329 Islamabad, Pakistan
| | - S Hussain
- National Tokamak Fusion Program, 3329 Islamabad, Pakistan
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