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Jun Ren.

Jun Ren

Research Assistant Professor

Biography

Research Assistant Professor​

December 2022 – Present

University of Tennessee-Knoxville – Department of Nuclear Engineering

  • Design and upgrade diagnostics for the Shape and Volume Rise (SVR) system in DIII-D.
  • Maintaining and operating the existing Surface Eroding.
  • Thermocouple (SETC) in DIII-D, and developing the SETC for modular divertor.
  • Execute the SAS-VW milestone experiment and compose the final report titled "Mitigate E×B Effects in SAS by Modest Change of Tile Shape to Improve Power Mitigation for Both Bt Directions.”
  • Investigating divertor detachment physics and analyzing heat flux profiles related to the SAS-VW experiments.
  • Directing the post-doc for developing the Retarding Field Analyzer.
Research Scientist​​

April 2020 – December 2022

University of Tennessee-Knoxville – Department of Nuclear Engineering​​

  • Collaborative work with the DIII-D Experimental Fusion Reactor at General Atomics and coordinate the collaborative researches involving the UT.
  • Maintain and operate the Surface Eroding Thermocouple (SETC) system in DIII-D and expand the SETC array, develop the new method of using SETC to measure the heat flux form non-charged particles.
  • Investigate the plasma detachment and core-edge integration via surface temperature measurement in various heat flux mitigation scheme.
  • Study the role of radiative heating and neutrals in surface heat flux in open divertor vs in closed divertor.
  • Direct the graduate student designing Retarding Field Analyzer and using it for divertor ion temperature measurement.
Post-Doc​​​​​

January 2016 – March 2020

University of Tennessee-Knoxville – Department of Nuclear Engineering​​

Principal Investigator: Dr. David Donovan

  • Constructed a SETC system on DIII-D for fast local heat flux measurement to study various divertor heat flux mitigation scheme and particle transport in the edge of plasma.
  • Investigated the roles of divertor closure and EB drift in setting heat flux profile in SAS divertor using SETC measurement.
  • Developing a Retarding Field Analyzer (RFA) system on DIII-D for ion distribution function (Ti) measurement at the divertor.
  • Collaborative worked with SNL (Sandia National Laboratories) on divertor Langmuir probes maintenance, upgradation and operations.
Graduate Researcher​​​​​​​

September 2011- July 2016

Institute of plasma physics, Chinese Academy of Sciences​​

  • Worked in Vacuum and Wall Conditioning group of EAST and contributed in running vacuum system and wall conditioning system on EAST.
  • Designed and constructed the Flowing Liquid Lithium Limiter (FLLL) system on EAST and HT-7 to develop the liquid metal operate technology and study the interaction between the liquid lithium and plasmas in magnetic confined fusion device.
  • Developed and calibrated the Low-Z impurity injection system on EAST including Lithium powder dropper and Lithium pellet injector.

Research

  • Develop state-of-the-art boundary diagnostics to measure the target heat flux.
  • Characterize the heat flux profile in the fusion device, understand the divertor physics and improve heat flux management.
  • Achieve high-performance operating scenarios integrated with high-power exhaust solutions in fusion devices by improving power dissipation in the divertor region (divertor detachment).
  • Test advanced materials to address the power-removal problem and suppress impurities generated by the process of Plasma-Surface Interaction (PSI).
  • Improve core plasma performance through wall conditioning, including lithium evaporation and power injection.

Education

  • PhD, Plasma Physics, Institute of Plasma Physics Chinese Academy of Sciences, Anhui, China 2016
  • BS, Metallurgical Engineering, Institute of Materials and Metallurgy, Northeastern University, Boston, Massachusetts, 2010

Professional Service

  • Member of American Physical Society
  • Member of American Nuclear Society
  • Member of Institute of Electrical and Electronics Engineers
  • Session chair for TOFE 2024 conference
  • Editorial Board Member in “Nuclear Science”

Awards and Recognitions

  • 2022 UT Nuclear Engineering Research Excellence Award

Publications

A full list of Ren's publications is available at his Google Scholar Profile.

  • J. Ren, D. C. Donovan, J. G. Watkins, H. Q. Wang, C. Lasnier, T. Looby, J. Canik, D. Rudakov, P. C. Stangeby, D. Thomas, and R. Boivin. Measurements of multiple heat flux components at the divertor target by using surface eroding thermocouples (invited), Rev Sci Instrum, 93: 103541, 2022.
  • J. Ren, D. C. Donovan, J. G. Watkins, H. Q. Wang, X. X. Ma, R. Maurizio, M. W. Shafer, D. Rudakov, P. C. Stangeby, D. Thomas, and S. Hong. Measurements of heat flux components due to charged and non-charged particles in DIII-D divertor near and under detachment, Nuclear Materials and Energy, 37: 101523, 2023.
  • J. Ren, D. Donovan, J. G. Watkins, H. Q. Wang, D. Rudakov, T. Looby, D. Thomas, and R. Boivin. A Method to Identify the Heat Flux From Photons and Neutrals at the Divertor Target, Ieee T Plasma Sci, 50: 4257-4261, 2022.
  • Ren J, Donovan D, Watkins J, Wang HQ, Rudakov D, Murphy C, Unterberg E, Thomas D, Boivin R. Development of Surface Eroding Thermocouples in Small Angle Slot Divertor in DIII-D. IEEE Transactions on Plasma Science P1-6,8,2019.
  • Ren J, Donovan DC, Watkins JG, Wang HQ, Thomas DM, and Boivin R. Experimental observation of heat flux mitigation during divertor detachment in the DIII-D small angle slot divertor. Nuclear Materials and Energy 26: 100887, 2021.
  • Ren J, Donovan D, Watkins J, Wang HQ, Rudakov D, Murphy C, McLean A, Lasnier C, Unterberg E, Thomas D, and Boivin R. The surface eroding thermocouple for fast heat flux measurement in DIII-D. Rev Sci Instrum 89: 10J122, 2018.
  • Ren J, Zuo GZ, Hu JS, Sun Z, Li JG, Zakharov LE, Ruzic DN, and Xu WY. Investigations on interactions between the flowing liquid lithium limiter and plasmas. Fusion Eng Des 102: 36-43, 2016.
  • Ren J, Zuo GZ, Hu JS, Sun Z, Yang QX, Li JG, Zakharov LE, Xie H, and Chen ZX. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak. Rev Sci Instrum 86: 023504, 2015.
  • Ren J, Hu JS, Zuo GZ, Sun Z, Li JG, Ruzic DN, and Zakharov LE. First results of flowing liquid lithium limiter in HT-7. Phys Scripta 2014: 014033, 2014.

 

Jun Ren.

Contact Information

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