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Benedikt Geiger

Benedikt Geiger

Assistant Professor

Benedikt Geiger is an Associate Professor in the Department of Nuclear Engineering and Engineering Physics at the University of Wisconsin – Madison. He serves as the principal investigator of the Helically Symmetric eXperiment (HSX), an optimized stellarator dedicated to exploring quasi-symmetry and investigating particle and heat transport in three-dimensional magnetic fields. In addition to his work on HSX, Prof. Geiger leads UW – Madison’s Turbulence and Spectroscopy Group, which operates advanced fluctuation diagnostics at major fusion facilities including the DIII-D tokamak, the W7-X stellarator, and the NSTX-U spherical tokamak.
Prof. Geiger earned his Ph.D. in 2013 through research conducted at the ASDEX Upgrade tokamak in Germany and was a group leader at the W7-X experiment prior to joining UW – Madison in 2019. His research interests span plasma spectroscopy, particle and heat transport, and the development and application of synthetic diagnostics. He is actively involved in the fusion research community, serving as Vice Chair of the National Stellarator Coordinating Committee (NSCC), a board member of the Transport Task Force (TTF) workshop, a member of the Coordinated Working Group Meeting (CWGM) organizing committee, and a board member of the International Stellarator and Heliotron Workshop (ISHW). Prof. Geiger is a recipient of the U.S. Department of Energy Early Career Award and was recently honored with a Grainger Institute for Engineering Professorship.

Department

Nuclear Engineering & Engineering Physics

Contact

519, Engineering Research Building
1500 Engineering Dr
Madison, WI

  • PhD 2013, Ludwig-Maximilians University
  • Diploma (MS) 2009, Ludwig-Maximilians University
  • Diploma Thesis 2009, Max-Planck institute for Physics

  • Experimental investigation of heat and particle confinement in high-temperature fusion plasmas

Affiliated Departments

  • 2025 Grainger Institute, Grainger Institute for Engineering Professorship
  • 2020 Dept. of Energy/FES, Early Career Award
  • 2017 Hans-Werner-Osthoff plasma physics award
  • 2014 American Physical Society (APS) and European Physical Society (EPS), Landau Spitzer Award
  • 2014 Max-Planck Society, Otto-Hahn-Medal
  • 2012 European Physical Society, Poster-Prize for Ph.D. students

  • Davies, R., Feng, Y., Boeyaert, D., Schmitt, J. C., Gerard, M. J., Garcia, K. A., Schmitz, O., Geiger, B., & Henneberg, S. A. (2024). A semi-automated algorithm for designing stellarator divertor and limiter plates and application to HSX. Nuclear Fusion, 64(12), 126044 https://doi.org/10.1088/1741-4326/ad8017
  • Goodman, W. R., & Geiger, B. (2024). Enhancing Thomson scattering polychromator performance with multi-pass spectral filters. Review of Scientific Instruments, 95(9), 093507 https://doi.org/10.1063/5.0219569
  • Edmondson, A., Albosta, R., Geiger, B., Gallenberger, T., Smith, D., Heidbrink, W. W., & Stratton, B. (2024). High speed fast-ion D-alpha spectrometer for the NSTX-U tokamak. Review of Scientific Instruments, 95(9), 093527 https://doi.org/10.1063/5.0219190
  • Swee, C., Geiger, B., Ford, O., O’Mullane, M., Poloskei, P., Reimold, F., Romba, T., Wegner, T., & Team, W. (2024). High-n Rydberg transition spectroscopy for heavy impurity transport studies in W7-X (invited). Review of Scientific Instruments, 95(9), 093539 https://doi.org/10.1063/5.0219589
  • Albosta, R., Geiger, B., McKee, G., Marchuk, O., Gallenberger, T., Khabanov, F., & Den Hartog, D. (2024). Measurement of Stark-split beam and carbon charge exchange emissions for simultaneous B-field and temperature/rotation analysis at DIII-D. Review of Scientific Instruments, 95(9), 093519 https://doi.org/10.1063/5.0219534
  • Swee, C., Geiger, B., Ford, O., Nornberg, M., O’Mullane, M., Poloskei, P., Reimold, F., Romba, T., Wegner, T., & Team, t. W. (2024). Impurity transport study based on measurement of visible wavelength high-n charge exchange transitions at W7-X. Nuclear Fusion, 64(8), 086062 https://doi.org/10.1088/1741-4326/ad5aad
  • Gill, K., Smith, D., Joung, S., Geiger, B., McKee, G., Zimmerman, J., Coffee, R., A Jalalvand,, & Kolemen, E. (2024). Real-time confinement regime detection in fusion plasmas with convolutional neural networks and high-bandwidth edge fluctuation measurements. Machine Learning: Science and Technology, 5(3), 035012 https://doi.org/10.1088/2632-2153/ad605e
  • Gerard, M. J., Pueschel, M. J., Geiger, B., Mackenbach, R. J., Duff, J. M., Faber, B. J., Hegna, C. C., & Terry, P. W. (2024). On the effect of flux-surface shaping on trapped-electron modes in quasi-helically symmetric stellarators. Physics of Plasmas, 31(5), 052501 https://doi.org/10.1063/5.0203569
  • Joung, S., Smith, D. R., McKee, G., Yan, Z., Gill, K., Zimmerman, J., Geiger, B., Coffee, R., O’Shea, F., Jalalvand, A., & Kolemen, E. (2024). Tokamak edge localized mode onset prediction with deep neural network and pedestal turbulence. Nuclear Fusion, 64(6), 066038 https://doi.org/10.1088/1741-4326/ad43fb
  • Poloskei, P. Z., Geiger, B., Jansen van Vuuren, A., Äkäslompolo, S., Ford, O., Spanier, A., Neelis, T., McNeely, P., Hartmann, D., & Team, t. W. (2023). Experimental characterization of the active and passive fast-ion H-alpha emission in W7-X using FIDASIM. Nuclear Fusion, 64(2), 026008 https://doi.org/10.1088/1741-4326/ad0dd4

  • E C E 890 - Pre-Dissertator's Research (Spring 2025)
  • E C E 990 - Dissertator's Research (Spring 2025)
  • N E 526 - Laboratory Course in Plasmas (Spring 2025)
  • N E 699 - Advanced Independent Study (Spring 2025)
  • N E 790 - Master's Research and Thesis (Spring 2025)
  • N E 890 - Pre-Dissertator's Research (Spring 2025)
  • N E 990 - Research and Thesis (Spring 2025)
  • E C E 890 - Pre-Dissertator's Research (Fall 2024)
  • E C E 990 - Dissertator's Research (Fall 2024)
  • N E 699 - Advanced Independent Study (Fall 2024)
  • N E 790 - Master's Research and Thesis (Fall 2024)
  • N E 890 - Pre-Dissertator's Research (Fall 2024)
  • N E 903 - Special Topics-Plasma Physics (Fall 2024)
  • N E 990 - Research and Thesis (Fall 2024)
  • E C E 890 - Pre-Dissertator's Research (Summer 2024)
  • E C E 990 - Dissertator's Research (Summer 2024)
  • N E 790 - Master's Research and Thesis (Summer 2024)
  • N E 890 - Pre-Dissertator's Research (Summer 2024)
  • N E 990 - Research and Thesis (Summer 2024)
  • E C E 790 - Master's Research (Spring 2024)
  • E C E 890 - Pre-Dissertator's Research (Spring 2024)
  • N E 526 - Laboratory Course in Plasmas (Spring 2024)
  • N E 699 - Advanced Independent Study (Spring 2024)
  • N E 790 - Master's Research and Thesis (Spring 2024)
  • N E 890 - Pre-Dissertator's Research (Spring 2024)
  • N E 990 - Research and Thesis (Spring 2024)
  • N E 427 - Nuclear Instrumentation Laboratory (Fall 2023)
  • N E 699 - Advanced Independent Study (Fall 2023)
  • N E 790 - Master's Research and Thesis (Fall 2023)
  • N E 890 - Pre-Dissertator's Research (Fall 2023)
  • N E 990 - Research and Thesis (Fall 2023)
  • N E 790 - Master's Research and Thesis (Summer 2023)
  • N E 890 - Pre-Dissertator's Research (Summer 2023)
  • N E 990 - Research and Thesis (Summer 2023)