Dedicated and results-driven plasma physicist with a PhD from the Institute for Plasma Research, India, and research experience at the ITER Organization, France. Currently a Research Fellow at Nanyang Technological University, Singapore, contributing to cutting-edge plasma simulations and fusion energy research. Developing my skills in gyrokinetic simulations, plasma turbulence analysis, and energetic particle studies. A collaborative team player with a strong academic background, proven research capabilities, and a passion for advancing scientific understanding in fusion energy and plasma physics.
My current research focuses on fast ion-driven Toroidal Alfven Eigenmodes (TAEs). My work aims to address the critical challenge of turbulence-induced thermal loses in fusion plasmas, which impact the efficiency of magnetic confinement devices. By combining analytical techniques with high-fidelity gyrokinetic simulations using GYSELA code, developed in CEA-Cadarache, France. This project comes under the Singapore Alliance with France for Fusion Energy (SAFE) framework. I am working to predict and control turbulence transport in reactor-grade plasmas. This research is geared toward exploring the interaction between turbulence and energetic particles.
As a Senior Research Fellow at Institute for Plasma Research, India, I focus on non-linear fluid simulations of the tokamak boundary region (Edge and SOL), which is highly turbulent due to interchange and drift wave instabilities. My research involves using the BOUT++ simulation framework to investigate turbulence-driven particle and heat transport. I have studied the effects of nitrogen gas seeding on plasma turbulence, equilibrium density, and electron temperature, finding localized radiation near the tokamak edge consistent with experimental observations from ADITYA-U. The inward transport of impurity ions, primarily in their first ionization state, is linked to plasma vorticity, sources and sinks, and the mass-to-charge ratio, with inward velocities of 500-1000 m/s. Additionally, I explored how effective gravity, induced by magnetic field gradients, affects impurity transport, with monopolar density holes driving inward transport and plasma blobs causing outward fluxes. The radiated power was found to fluctuate at 5-20 kHz, closely matching interchange-driven turbulence. I have also examined the impact of ion temperature gradients on impurity ion dynamics and coherent structure propagation, with a particular focus on impurity transport associated with plasma density holes as observed in experiments.
Journal Publications
1. Raj, S., Bisai, N., Shankar, V., & Sen, A. (2020). "Effects of nitrogen seeding in a tokamak plasma". Physics of Plasmas, 27(12), 122302.
2. Raj, S., Bisai, N., Shankar, V., Sen, A., Ghosh, J., Tanna, R. L., ... & Singh, K.(2022). "Studies on impurity seeding and transport in edge and SOL of tokamak plasma". Nuclear Fusion, 62(3), 036001.
3. Raj, Shrish, Nirmal Bisai, Vijay Shankar, and Abhijit Sen. "Argon, neon, and nitrogen impurity transport in the edge and SOL regions of a tokamak." Physics of Plasmas 30, no. 6 (2023).
4. Raj, S., Bisai, N., Shankar, V., & Sen, A. (2023). "Effect of ion temperature on the dynamics of seeded impurities in the edge and SOL regions of a tokamak". (manuscript under preparation).
5. Shankar, V., Bisai, N., Raj, S., & Sen, A. (2021). "Finite electron temperature gradient effects on blob formation in the scrape-off layer of a tokamak plasma". Nuclear Fusion, 61(6), 066008.
6. Shankar, V., Bisai, N., Raj, S., & Sen, A. (2022). "Edge biasing and its impact on the edge and SOL turbulence". Nuclear Fusion.
7. Shankar, V., Bisai, N., Raj, S., & Sen, A. (2023). Impact of edge biasing on the cross-field transport and power spectra. Physics of Plasmas, 30(6).
Conference Presentations
1. Plasma Science Society of India-December 3-6, 2019 Title: Impact of Nitrogen gas seeding on Edge and SOL plasma turbulence.
2. International e-Conference on Plasma Theory and Simulations- 14 to 15, September 2020. Title: Nitrogen seeding in a tokamak plasma: non-coronal effects.
3. AAPPS-DPP 2021- 26 September to October 1. Title: Impact of gravity on dynamics of seeded impurity ions in tokamak plasma.
4. 64th Annual Meeting of the APS Division of Plasma Physics 2022-17 to 21, October. Title: Effect of turbulence on impurity transport in the edge and SOL region.
5. 49th conference on plasma physics EPS-2023, 03 July to 07 July. Title: Effect of ion temperature on the dynamics of seeded impurities in the edge and SOL regions of a tokamak plasma.
6. 8th Asia-Pacific Conference on Plasma Physics (AAPPS-DPP2024), 04 November to 08 November. Title: Studies of Impurity Transport in tokamak edge and SOL using tracer particle simulations.
I have a deep passion for music, with experience in singing and playing instruments like the guitar and Casio keyboard. Engaging in sports such as cricket, football, volleyball, badminton, and carrom has helped me develop teamwork, leadership, and strategic thinking skills. These activities contribute to my personal growth, offering a balance between creativity, physical activity, and mental relaxation.