A5026458761- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Astrophysics and Star Formation Studies
- Laser-Plasma Interactions and Diagnostics
- Pulsars and Gravitational Waves Research
- Magnetic Field Sensors Techniques
- Quantum chaos and dynamical systems
- Metal Forming Simulation Techniques
- Atomic and Subatomic Physics Research
- Frequency Control in Power Systems
- Wireless Power Transfer Systems
- Geophysics and Sensor Technology
- High voltage insulation and dielectric phenomena
- Scientific Research and Discoveries
- Advanced Fiber Optic Sensors
- Nonlinear Photonic Systems
- Atomic and Molecular Physics
- Dust and Plasma Wave Phenomena
- Radiation Detection and Scintillator Technologies
- Earthquake Detection and Analysis
Fusion Academy
2017-2025
Fusion (United States)
2017-2025
Institute for Advanced Study
2021-2025
Plasma Technology (United States)
2017-2025
Massachusetts Institute of Technology
2018-2025
Flatiron Health (United States)
2023-2025
Flatiron Institute
2023-2025
IIT@MIT
2017
Johannes Gutenberg University Mainz
1991
Hitotsubashi University
1991
The SPARC tokamak is a critical next step towards commercial fusion energy. designed as high-field ( $B_0 = 12.2$ T), compact $R_0 1.85$ m, $a 0.57$ m), superconducting, D-T with the goal of producing gain $Q>2$ from magnetically confined plasma for first time. Currently under design, will continue path Alcator series tokamaks, utilizing new magnets based on rare earth barium copper oxide high-temperature superconductors to achieve high performance in device. achievable conservative...
Experiments on the Alcator C-Mod tokamak have utilized reactor-relevant magnetic fields to sustain substantially higher pedestal pressure than in other devices and allow close approach ITER H-mode baseline target of 90 kPa. The EPED model, which couples physics transport driven by kinetic ballooning modes MHD instabilities arising from peeling-ballooning modes, predicts profile at onset edge-localized (ELMs), yields lowest order a critical-βN like behavior for pedestal: ( fixed edge q)....
New results on the I-mode regime of operation Alcator C-Mod tokamak are reported. This ELM-free features high energy confinement and a steep temperature pedestal, while particle remains at L-mode levels, giving stationary density avoiding impurity accumulation. has now been obtained over nearly all magnetic fields currents possible in this field (Ip 0.55–1.7 MA, BT 2.8–8 T) using configuration with B × ∇B drift away from X-point. Results 8 T confirm that L–I power threshold varies only...
This paper presents investigations on the role of edge ion heat flux for transitions from L-mode to H-mode in Alcator C-Mod. Previous results ASDEX Upgrade tokamak indicated that a critical value per particle is needed transition. Analysis C-Mod data confirms this result. The indeed found increase linearly with density at given magnetic field and plasma current. Furthermore, indicate L-H transition also increases field. Combining yields general expression These are discussed point view...
Abstract The secular evolution of disk galaxies is largely driven by resonances between the orbits “particles” (stars or dark matter) and rotation non-axisymmetric features (spiral arms a bar). Such may also explain kinematic photometric observed in Milky Way external galaxies. In simplified cases, these resonant interactions are well understood: for instance, dynamics test particle trapped near resonance steadily rotating bar easily analyzed using angle-action tools pioneered Binney,...
Kinetic theory of particles near resonances is a current topic discussion in plasma physics and astrophysics. We extend this to the kinetic interaction between alpha (energetic predicted exist large quantities next-generation fusion experiments) neoclassical tearing mode (NTM), resistively-driven perturbation which sometimes exists tokamak. develop quasilinear treatment an NTM, showing why NTM can be source significant passing particle transport tokamaks. The limitations on constrain our...
Potential loss of energetic ions including alphas and radio-frequency tail due to classical orbit effects magnetohydrodynamic instabilities (MHD) are central physics issues in the design experimental programme SPARC tokamak. The expected fusion alpha power ripple-induced transport is computed for tokamak by ASCOT SPIRAL orbit-simulation codes, assess surface heating plasma-facing components. We find good agreement between simulation results not only integrated quantities (fraction loss) but...
Recent Alcator C-Mod experiments have explored access to and characteristics of H-modes at magnetic fields approaching 8 T, the highest field achieved date in a diverted tokamak. The originated from L-mode densities ranging , allowing insight into density dependence H-mode power threshold high field. This is compared predictions ITPA scaling law ([1]), finding that approximately accurate 7.8 T. However, underpredicted lower previous ([2]), suggesting overall on weaker than predicted by law....
Pulsar radio emission may be generated in pair discharges which fill the pulsar magnetosphere with plasma as an accelerating electric field is screened by freshly created pairs. In this Letter we develop a simplified analytic theory for screening of these and use it to estimate total luminosity spectrum. The discharge has three stages. First, first time starts oscillate. Next, nonlinear phase occurs. phase, amplitude experiences strong damping because dramatically changes momenta newly This...
Sweet–Parker current sheets in high Lundquist number plasmas are unstable to tearing, suggesting they will not form physical systems. Understanding magnetic reconnection thus requires study of the stability a sheet as it forms. Formation can occur due sheared, sub-Alfvénic incompressible flows which narrow sheet. Standard tearing theory (Furth et al. Phys. Fluids , vol. 6 (4), 1963, pp. 459–484, Rutherford, 16 (11), 1973, 1903–1908, Coppi Fizika Plazmy 2, 1976, 961–966) is immediately...
Upcoming tokamak experiments fueled with deuterium and tritium are expected to have large alpha particle populations. Such motivate new attention the theory of confinement transport. A key topic is interaction alphas perturbations fields, including those from ripple magnetohydrodynamic modes like Alfv\'{e}n eigenmodes. These can transport alphas, leading changed localization heating, loss power, damage device walls. Alpha these often studied single theory. In contrast, we derive a drift...
Abstract In high-Lundquist-number plasmas, reconnection proceeds via the onset of tearing, followed by a nonlinear phase during which plasmoids continuously form, merge, and are ejected from current sheet (CS). This process is understood in fully ionized, magnetohydrodynamic plasmas. However, many plasma environments, such as star-forming molecular clouds solar chromosphere, poorly ionized. We use theory computation to study tearing-mediated ionized systems. this paper, we focus on linear...
Changes in the core intrinsic toroidal rotation velocity following L- to H- and I-mode transitions have been investigated Alcator C-Mod tokamak plasmas. The magnitude of co-current increments is found increase with pedestal temperature gradient , decrease magnetic field. These results are captured quantitatively by a model fluctuation entropy balance which gives Mach number an ITG turbulence dominant regime. agreement between experiment theory confidence for extrapolation future devices...
Alpha particle confinement is one of the most demanding issues for stellarators. It now seems clear that it possible to design optimized stellarators confine background plasma at near tokamak radial transport levels. Moreover, adequate collisionless alpha in core a highly stellarator. Here, collisional barely trapped alphas an stellarator considered by accounting resonance due reversal direction drift within flux surface and investigating sensitive role magnetic shear keeping this close...
Recently-proposed tokamak concepts use magnetic fields up to 12 T, far higher than in conventional devices, reduce size and cost. Theoretical computational study of trends plasma behavior with increasing field strength is critical such proposed devices. This paper considers Alfvén eigenmode (AE) stability. Energetic particles, including alphas from D-T fusion, can destabilize AEs, possibly causing loss alpha heat damage the device. AEs are sensitive device via dependence resonances, particle...
The velocity dependent resonant interaction of particles with applied radiofrequency (rf) waves during heating and current drive in the presence pitch angle scattering collisions gives rise to narrow collisional space boundary layers that dramatically enhance role as recently shown by Catto ( J. Plasma Phys. , vol. 86, 2020, 815860302). behaviour is a generalization layer forms Landau damping found Johnston Fluids 14, 1971, pp. 2719–2726) Auerbach 20, 1977, 1836–1844). For wave parallel...
A general procedure for understanding plasma behaviour when resonant wave–particle interactions are the sole destabilizing and transport mechanism or only heating and/or current drive source is highlighted without recourse to involved numerical analytical treatments. These phenomena characterized by that appears be collisionless even though collisions play a central role in narrow collisional boundary layers. The order of magnitude estimates, which include nonlinear effects, shown provide...
This article is the first design study of a combined interferometer and polarimeter on compact, high-field, high-density, net-energy tokamak. Recent advances in superconducting technology have made possible designs for high magnetic field fusion power plants, such as ARC [Sorbom et al., Fusion Eng. Des. 100, 378 (2015)], experiments, SPARC [Greenwald PSFC Report No. RR-18-2 (2018)]. These new create both challenges opportunities plasma diagnostics. The diagnostic proposed this work, called...
Kinetic theory of particles near resonances is a current topic discussion in plasma physics and astrophysics. We extend this to the kinetic interaction between alpha (energetic predicted exist large quantities next-generation fusion experiments) neoclassical tearing mode (NTM), resistively-driven perturbation that sometimes exists tokamak. develop quasilinear treatment alphas an NTM, showing why NTM can be source significant passing particle transport tokamaks. The limitations on constrain...
The secular evolution of disk galaxies is largely driven by resonances between the orbits 'particles' (stars or dark matter) and rotation non-axisymmetric features (spiral arms a bar). Such may also explain kinematic photometric observed in Milky Way external galaxies. In simplified cases, these resonant interactions are well understood: for instance, dynamics test particle trapped near resonance steadily rotating bar easily analyzed using angle-action tools pioneered Binney, Monari others....