S. Munaretto
A5036033899- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Semiconductor materials and devices
- Nuclear reactor physics and engineering
- Characterization and Applications of Magnetic Nanoparticles
- Non-Destructive Testing Techniques
- Magnetic Field Sensors Techniques
- Advancements in Semiconductor Devices and Circuit Design
- Dust and Plasma Wave Phenomena
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- 3D Shape Modeling and Analysis
- Radiation Effects in Electronics
- Neural Networks and Applications
- Spacecraft and Cryogenic Technologies
- Physics of Superconductivity and Magnetism
- Thin-Film Transistor Technologies
- Electrical and Bioimpedance Tomography
- Power System Reliability and Maintenance
Princeton Plasma Physics Laboratory
2021-2024
University of Wisconsin–Madison
2014-2022
General Atomics (United States)
2018-2022
Oak Ridge National Laboratory
2022
National Agency for New Technologies, Energy and Sustainable Economic Development
2009-2013
Forschungszentrum Jülich
2013
Abstract The objectives of NSTX-U research are to reinforce the advantages STs while addressing challenges. To extend confinement physics low- A , high beta plasmas lower collisionality levels, understanding transport mechanisms that set performance and pedestal profiles is being advanced through gyrokinetic simulations, reduced model development, comparison NSTX experiment, as well improved simulation RF heating. develop stable non-inductive scenarios needed for steady-state operation,...
Abstract Using a single toroidal array of coils to reduce the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>m</mml:mi> <mml:mo>,</mml:mo> <mml:mi>n</mml:mi> <mml:mo>=</mml:mo> <mml:mn>2</mml:mn> <mml:mn>1</mml:mn> </mml:mrow> </mml:math> resonant error field (EF) produced by misalignment axisymmetric in SPARC can result enhancement local divertor heat fluxes. Managing high fluxes ( <mml:msub> <mml:mi>q</mml:mi> <mml:mo>∥</mml:mo> </mml:msub>...
Global linear electromagnetic gyrokinetic simulations of micro-tearing modes (MTMs) growing in the wide pedestal ELM-free NSTX discharge #132 588 are reported. Two branches near surfaces safety factor q = 4 (pedestal top) and q=5–6 (pedestal) simulated. The frequencies these MTMs with low toroidal mode number (n ranging from 3 to 6) agreement ones quasi-coherent fluctuations present on magnetic spectrogram. No kinetic ballooning (KBM) is observed at experimental values β; instead, plasma...
The reversed field pinch configuration is characterized by the presence of magnetic structures both in core and at edge: core, high plasma current spontaneous development a helical structure accompanied appearance internal electron transport barriers; edge strong pressure gradients, identifying an barrier, are observed too, related to position reversal surface.
New edge diagnostics and detailed analysis of magnetic topology have significantly improved the comprehension processes developing at boundary a reversed-field pinch (RFP) plasma in RFX-mod ( = 0.46 m, R 2 m). An upper critical density n C ≈ 0.4 G Greenwald density) is found to limit operational space for quasi-single helical (QSH) regime: reconstructions diagnostic observations suggest that this due plasma–wall interaction which determines toroidally poloidally localized accumulation...
This paper presents a multi-machine, multi-parameter scaling law for the n = 2 core resonant error field threshold that leads to penetration, locked modes, and disruptions. Here, is toroidal harmonic of non-axisymmetric (EF). While density scalings have been reported by individual tokamaks in past, this work performs regression across comprehensive range densities, fields, pressures accessible three devices using common metric quantify EF each device. The used amount overlap between an...
Novel disruption prevention solutions spanning a range of control regimes are being developed and tested on DIII-D to enable ITER success. First, new real-time algorithm has been for regulating nearness stability limits maintaining safety-margins. Its first application reliable vertical displacement events (VDEs) by adjusting plasma elongation (κ) the inner-gap between inner-wall in response open-loop VDE growth rate (γ) estimators. VDEs were robustly prevented up average rates 800 rad s−1...
The full three-dimensional (3D) approach is now becoming an important issue for all magnetic confinement configurations. It a necessary condition the stellarator but also tokamak and reversed field pinch (RFP) cannot be completely described in axisymmetric framework. For RFP observation of self-sustained helical configurations with improved plasma performances require better description order to assess new view on this configuration. In framework configuration studies RFX-mod have been...
This paper summarizes the main achievements of RFX fusion science program in period between 2008 and 2010 IAEA Fusion Energy Conferences. RFX-mod is largest reversed field pinch world, equipped with a system 192 coils for active control MHD stability. The discovery understanding helical states electron internal transport barriers core temperature >1.5 keV significantly advances perspectives configuration. Optimized experiments plasma current up to 1.8 MA have been realized, confirming...
Abstract Beam modulation effects on Alfvén eigenmode stability have been investigated in a recent DIII-D experiment and show that variations neutral beam period can an impact the driven spectrum resultant fast ion transport despite similar time-averaged input power. The was carried out during current ramp phase of L-mode discharges heated with sub-Alfvénic 50–80 kV deuterium beams drive variety eigenmodes unstable. two interleaved different tangency radii varied from shot to order modify...
Single Helical Axis (SHAx) states obtained in high current reversed field pinch (RFP) plasmas display, aside from a dominant mode the m=1 spectrum, also m=0 mode, with same toroidal number as one. The two modes have fixed phase relationship. island chain created by across reversal surface gives rise, at shallow of field, to an X-point structure which separates last closed flux first wall, creating divertor-like configuration. plasma-wall interaction is found be related connection length...
Abstract The mission of the low aspect ratio spherical tokamak NSTX-U is to advance physics basis and technical solutions required for optimizing configuration next-step steady-state fusion devices. will ultimately operate at up 2 MA plasma current 1 T toroidal field on axis 5 s, has available 15 MW neutral beam injection power different tangency radii 6 high harmonic fast wave heating. With these capabilities develop understanding control tools ramp-up sustain performance fully...
It is well documented that the central electron temperature in national spherical torus experiment (NSTX) remains largely unchanged as external heating power, and hence normalized volume averaged plasma pressure β increases [Stutman, Phys. Rev. Lett. 102, 115002 (2009)PRLTAO0031-900710.1103/PhysRevLett.102.115002]. Here we present a hypothesis low n, driven ideal magnetohydrodynamic (MHD) instabilities are nondisruptive, can break magnetic surfaces region thereby flatten profiles. We...
We use the 3D magnetohydrodynamic (MHD) code M3D-C1 [Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)] to examine MHD stability and subsequent evolution of NSTX shot 129169. This discharge had a period with non-monotonic safety factor profile, q (reversed shear), which was terminated by event that abruptly lowered central factor, q0, greatly reduced peakedness pressure profile. show equilibrium just before occurred linearly unstable many pressure-driven infernal modes. Modes toroidal...
Edge localized mode (ELM) suppression has been achieved in the DIII-D tokamak using mixed toroidal and 3 harmonic resonant magnetic perturbations (RMPs). Here is number. It observed that RMPs lower threshold current for ELM compared to single case. The decreased suggests offer a better path control. error field effect studied by superimposing correction upon phase scan, which shows it possible suppress correct simultaneously. plasma response measured sensors plays key role RMPs. A nonlinear...
In the reversed field pinch RFX-mod at highest plasma current of 2 MA, when error fields are not effectively feedback controlled, localized thermal loads up to tens MW m−2 can be produced. The graphite tiles withstand such high power loads, but hydrogen retention makes density control extremely difficult. Several wall conditioning techniques have been optimized in last campaigns, including helium glow discharge cleaning and boronization by diborane discharges. More recently, lithium has...
This paper reports the highlights of RFX-mod fusion science programme since last 2010 IAEA Fusion Energy Conference. The focused on two main goals: exploring potential reversed field pinch (RFP) magnetic configuration and contributing to solution key technology problems in roadmap ITER. Active control several plasma parameters has been a tool this endeavour. New upgrades system for active magnetohydrodynamic (MHD) stability are underway will be presented paper. Unique among existing devices,...
The successful application of three-dimensional (3D) magnetohydrodynamic (MHD) spectroscopy in the stable DIII-D and EAST plasmas enables to directly extract multi-mode plasma transfer function tokamak experiments. not only reveals contribution each dominant MHD eigenmode multi-model response, but also quantifies corresponding eigenvalue which is critical stability index mode. method performs active detection by utilizing upper lower rows internal coils scan frequency poloidal spectrum...
An overview of recent results from the MST reversed field pinch programme is presented. With neutral beam injection, bursty energetic particle (EP) modes are observed. The profiles magnetic and density fluctuations associated with these EP measured using a far infrared interferometer–polarimeter. Equilibrium reconstructions quasi-single-helicity 3D helical state provided by V3FIT code that now incorporates several MST's advanced diagnostics. orientation structure controlled new resonant...
Abstract The successful application of three-dimensional (3D) magnetohydrodynamic (MHD) spectroscopy enables us to identify the multi-mode eigenvalues in DIII-D and KSTAR tokamak experiments with stable plasmas. temporal evolution multi-modes’ stabilities have been detected. new method is numerically efficient allowing real time detection MHD modes’ during discharge. performs active plasma stability by utilizing upper lower rows internal non-axisymmetric coils apply a wide variety 3D fields....
To aid in diagnosis of 3D equilibria the Madison Symmetric Torus, it has become necessary to control orientation equilibria. In reversed field pinch experiments a transition equilibrium is common with sufficiently large plasma current (and Lundquist number). Diagnosis this state hampered by fact that helical structure stationary but an varies shot-to-shot. A resonant magnetic perturbation (RMP) technique been developed vary controllably and optimized minimize wall interaction due its use....
This paper explores the behavior of runaway electrons in tokamak plasmas at low electron density, plasma current, and magnetic field using experimental data from Madison Symmetric Torus (MST) computational NIMROD nonlinear resistive 3D MHD code. Density thresholds for onset suppression are determined experimentally steady plasmas, with a population electrons, resonant perturbations different poloidal mode numbers applied. Poloidal number m = 3 suppress while 1 have little effect. difference...
Plasma–wall interaction is one of the most important issues that present magnetic confinement devices have to face. In RFX-mod reversed field pinch experiment plasma–wall has become a hard point increasing plasma current up maximum design value 2 MA, since in this case local power deposition can be as high 10 MW m −2 . Since first wall entirely covered by graphite tiles different techniques been tested control hydrogen influx: He glow discharges cleaning, at currents, boronization and...
This paper extends the analysis first presented in Jardin et al. [Phys. Rev. Lett. 128, 245001 (2022)] to more thoroughly examine stability of spherical torus equilibrium ideal magnetohydrodynamic (MHD) infernal modes and their nonlinear consequences. We demonstrate that a 3D resistive simulation NSTX discharge, anomalous transport can occur due these instabilities. generate family differing β use this show instabilities could explain experimentally observed flattening electron temperature...