V. Bandaru
A5078377816- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Fluid Dynamics and Turbulent Flows
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Characterization and Applications of Magnetic Nanoparticles
- Nuclear reactor physics and engineering
- Metallurgical Processes and Thermodynamics
- Geomagnetism and Paleomagnetism Studies
- Particle Accelerators and Free-Electron Lasers
- Laser-Plasma Interactions and Diagnostics
- Electron and X-Ray Spectroscopy Techniques
- Magnetic and Electromagnetic Effects
- Particle Dynamics in Fluid Flows
- Laser-induced spectroscopy and plasma
- Plant Water Relations and Carbon Dynamics
- Fluid Dynamics and Vibration Analysis
- Hydrogen Storage and Materials
- Geophysical and Geoelectrical Methods
- High voltage insulation and dielectric phenomena
- Semiconductor materials and devices
- Nanofluid Flow and Heat Transfer
Max Planck Institute for Plasma Physics
2017-2025
Indian Institute of Technology Guwahati
2024
CEA Cadarache
2021
Max Planck Society
2017-2021
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2021
Technische Universität Ilmenau
2015-2018
JOREK is a massively parallel fully implicit non-linear extended MHD code for realistic tokamak X-point plasmas. It has become widely used versatile studying large-scale plasma instabilities and their control developed in an international community. This article gives comprehensive overview of the physics models implemented, numerical methods applied solving equations studies performed with code. A dedicated section highlights some verification work done hierarchy different available...
Abstract The JET 2019–2020 scientific and technological programme exploited the results of years concerted engineering work, including ITER-like wall (ILW: Be W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power 2019–2020, tested technical procedural preparation for safe operation with tritium. Research along three complementary axes yielded wealth new results. Firstly, plasma delivered scenarios...
Abstract In 2021 JET exploited its unique capabilities to operate with T and D–T fuel an ITER-like Be/W wall (JET-ILW). This second major campaign (DTE2), after DTE1 in 1997, represented the culmination of a series enhancements—new fusion diagnostics, new injection capabilities, refurbishment plant, increased auxiliary heating, in-vessel calibration 14 MeV neutron yield monitors—as well as significant advances plasma theory modelling community. DTE2 was complemented by sequence isotope...
Abstract The most efficient and promising operational regime for the International Thermonuclear Experimental Reactor tokamak is high-confinement mode. In this regime, however, periodic relaxations of plasma edge can occur. These edge-localized modes pose a threat to integrity fusion device. Here we reveal strong impact energetic ions on spatio-temporal structure in tokamaks using nonlinear hybrid kinetic–magnetohydrodynamic simulations. A resonant interaction between fast at electromagnetic...
Abstract For the past several years, JET scientific programme (Pamela et al 2007 Fusion Eng. Des . 82 590) has been engaged in a multi-campaign effort, including experiments D, H and T, leading up to 2020 first with 50%/50% D–T mixtures since 1997 ever plasmas ITER mix of plasma-facing component materials. this purpose, concerted physics technology was launched view prepare campaign (DTE2). This paper addresses key elements developed by directly contributing preparation. intense preparation...
For the first time it is experimentally demonstrated on JET tokamak that a combination of low impurity concentration bulk plasma and large magnetohydrodynamic instabilities able to suppress relativistic electron beams without measurable heat loads onto facing components. Magnetohydrodynamic simulations instability modeling postinstability confirm prompt loss runaways absence regeneration during final current collapse. These surprising findings motivate new approach dissipate runaway...
Abstract In ITER, disruption-born runaway electrons (REs), unless mitigated, are expected to form a several Mega-Ampere beam that ultimately intercepts the first wall leading melting of plasma facing components. Developing successful mitigation strategy therefore requires modeling takes into account coupling between REs and MHD during formation termination beam, along with estimates for loads can be compared design values. Using JOREK code, this work aims provide latter by presenting novel...
The objective of thermonuclear fusion consists producing electricity from the coalescence light nuclei in high temperature plasmas. most promising route to envisages confinement such plasmas with magnetic fields, whose studied configuration is tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one main potential showstoppers on a commercial reactor. In this work we report how, deploying innovative analysis methods thousands JET experiments covering isotopic...
Abstract The vertical motion and shrinking of the cold plasma column after a tokamak disruption leads to natural decrease in edge safety factor when most current is carried by runaway electrons (REs). Reaching low can potentially cause strong instability. We present magnetohydrodynamic simulations termination post-disruption plateau-phase RE beam ITER falls close two. Growth instabilities observed result stochastization magnetic field prompt loss REs. As impact must be mitigated ITER, effect...
Relativistic electron (RE) beams at high current density (low safety factor, qa) yet very low free-electron accessed with D2 secondary injection in the DIII-D and JET tokamak are found to exhibit large-scale MHD instabilities that benignly terminate RE beam. In JET, this technique has enabled termination of MA-level currents without measurable first-wall heating. This scenario thus offers an unexpected alternate pathway achieve mitigation collisional dissipation. Benign is explained by two...
Abstract Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER EU DEMO. A major objective the AUG programme is to shed light underlying physics confinement, stability, plasma exhaust order allow reliable extrapolation results obtained present day machines these reactor-grade devices. Concerning pedestal physics, mitigation edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found be consistent with reduction linear...
The Alfvén instability nonlinearly excited the energetic-particle-driven geodesic acoustic mode on ASDEX-Upgrade tokamak, as demonstrated experimentally. mechanism of excitation and nonlinear evolution is not yet fully understood. In present work, a first-principles simulation using MEGA code investigated properties in both linear growth saturated phases. Here we show that successfully reproduced coexistence these two modes, agreed with experimental results well. Conclusive evidence showed...
Abstract Runaway electron loads onto material structures are a major concern for future large tokamaks due to the efficient avalanching at high plasma currents. 
Here, we perform predictive numerical studies using JOREK code plausible configuration in European DEMO fusion power plant, focusing this paper on scenario where highest multi-ampere runaway beam is formed.
The work first comprises axisymmetric predictions of formation mitigated and simultaneous vertical motion loss...
We present two-dimensional global simulations of mitigated and vertically unstable disruptions in ITER the presence runaway electrons (REs). An elongated plasma free-boundary equilibrium is subjected to an artificial thermal quench (TQ) current profile flattening, followed by one or more massive material injections a RE avalanche. Scenarios major as well upward downward vertical displacement events are considered. Results provide important insights into effects formation, post TQ profile,...
Abstract Disruptions present one of the leading concerns for reliable tokamak operation. The acceleration electrons from thermal bulk to relativistic energies, so-called runaway electron (RE) generation, is in particular a problem future high current machines such as ITER. Accurately predicting generation and impact REs therefore essential making informed decisions concerning machine design use disruption mitigation systems. This requires high-fidelity modeling also accounting large MHD...
Abstract On the basis of several recent breakthroughs in fusion research, many activities have been launched around world to develop power plants on fastest possible time scale. In this context, high-fidelity simulations plasma behavior large supercomputers provide one main pathways accelerating progress by guiding crucial design decisions. When it comes determining energy confinement a magnetic device, which is key quantity interest, gyrokinetic turbulence are considered approach choice –...
Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle role plasma fueling shape for onset small ELM regimes. On both devices, regimes with high confinement are achieved if only two conditions fulfilled at same time. Firstly, density separatrix must be large enough (), leading pressure profile flattening separatrix, which stabilizes type-I ELMs. Secondly, magnetic configuration close double null (DN), reduction shear in...
Abstract The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance physics base of ITER and DEMO. Here, full tungsten wall is a key asset for extrapolating future devices. high overall heating power, flexible mix comprehensive diagnostic set allows studies ranging from mimicking scrape-off-layer divertor conditions DEMO at density fully non-inductive operation ( q 95 = 5.5, ) low density. Higher installed electron cyclotron...
Abstract A runaway electron (RE) fluid model is used to perform non-linear magnetohydrodynamic simulations of a relativistic beam termination event in JET. The case considered that post-disruption low density cold plasma the plateau phase, wherein high-Z impurities have been largely flushed out via deuterium second injection (Shot:95135). Details experiment are found separate publications. Our studies reveal combination and hollow current profile which confirmed by experimental causes fast...
Abstract Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at JET investigate ways prevent their generation or suppress them if avoidance is not sufficient. Avoidance possible SPI contains sufficiently low fraction high-Z material, it fired early in advance disruption prone runaway generation. These results are consistent with previous similar...
The boundary layer structure of the velocity and temperature fields in turbulent Rayleigh-Benard flows closed cylindrical cells unit aspect ratio is revisited from a transitional viscous perspective. When Rayleigh number large enough, dynamics at bottom top plates can be separated into an impact region downwelling plumes, ejection upwelling plumes interior away side walls. latter dominated by shear large-scale circulation (LSC) roll which fills whole cell continuously varies its orientation....
For the simulation of disruptions in tokamak fusion plasmas, a fluid model describing evolution relativistic runaway electrons and their interaction with background plasma is presented. The overall aim to self-consistently describe nonlinear coupled (REs) instabilities during disruptions. In this model, are considered as separate species which initial seed generated through Dreicer source, eventually grows by avalanche mechanism (further relevant source mechanisms can easily be added)....
Abstract An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling AUG discharges was established which able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In center, theoretical predictions current redistribution by a dynamo effect were confirmed experimentally. For core transport, stabilizing fast ion distributions turbulent transport shown be important explain isotope and...