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Plasma Science and Fusion Center

Massachusetts Institute of Technology


johan frenje

Principal Research Scientist

johan frenje

MIT Plasma Science & Fusion Center


Phone: (617) 452-4941

Address: Room NW17-235

Related links: High-Energy-Density Physics Division

Biographical Sketch

Johan began his Ph.D. studies at Uppsala University, Sweden. His graduate work, which was funded by the Swedish Natural Science Research Council, involved the development of a novel neutron spectrometer for the Joint European Torus (JET) at Culham Laboratories in UK. The spectrometer was installed in 1996 and subsequently used during many deuterium (D2) campaigns and the first high-power deuterium-tritium (DT) campaign in 1997. Time-resolved neutron spectra from triton burn-up in strongly transient D2 plasmas were obtained for the first time and compared to simulations. During the high-power DT campaign, information about toroidal plasma rotation, fast-ion components in radio-frequency and neutral beam heated plasmas was also obtained for the first time using neutron spectrometry. Overall, his work has according to many experts in the field been instrumental for the development of neutron spectrometry for Tokamak fusion plasmas.


At MIT, his research focuses on studies of ICF plasmas. He was the lead scientist in developing a novel burn-history diagnostic [the proton temporal diagnostic (PTD)] for studies of capsule-implosion dynamics previously unattainable. Utilizing this diagnostic together with other nuclear diagnostics, accurate time-resolved studies of the nature of the D3He and the DD burn were performed. In particular, studies of the shock-bang time and evolution of ion temperature (Ti) were conducted for the first time. This work resulted in an invitation to present these results at the American Physical Society Division of Plasma Physics held in Albuquerque in 2003.


He is currently the responsible scientist for two neutron spectrometers [called Magnetic Recoil Spectrometers (MRS)], one at OMEGA and one at the NIF, for measurements of the absolute neutron spectrum in the range 5 to 30 MeV, from which areal density (ρR), ion temperature (Ti) and yield can be directly inferred for cryogenic DT implosions. Using the MRS, high ρR cryogenic DT implosions were probed for the first time using down-scattered neutrons at OMEGA. The ρR data obtained with the MRS have been essential for understanding how the assembly of the fuel occurs, and for guiding the cryogenic program at LLE to ρR values up to ~300 mg/cm2. The MRS on the NIF has also provided data that have been essential to the progress of NIC. Recent data obtained with the MRS in September 2011 indicate that the implosion performance, characterized by the Experimental Ignition Threshold Factor (ITFX) has improved about 50 times since the first shot a year earlier. Overall, this work has resulted in six invited talks since 2008.


Johan has also pioneered a new field of research, called plasma nuclear science, which blends the disciplines of plasma and nuclear physics. In his pioneering experiment, he demonstrated for the first time that an ICF facility and high-energy-density plasma can be used to study basic nuclear physics. In particular, the differential cross section for the elastic neutron-triton (n-3H) and neutron-deuteron (n-2H) scattering at 14.1 MeV was measured with significantly higher accuracy than achieved in previous accelerator experiments.


Overall, Johan has authored/co-authored about 170 peer-reviewed journal papers, and delivered 12 invited and 1 plenary talks . He has also been a panel member of the DOE High-Energy-Density Laboratory Physics (HEDLP) ReNew Panel 2009, a member of the NNSA Basic Research Directions on User Science at the NIF panel in 2010, a member of the board who defined and oversees the Policy on Data and Dissemination of Results for National Ignition Campaign (2011-2012), and panel lead for the Stagnation properties and burn panel, which was part of the NNSA Review on Science of Fusion Ignition in 2012. He is a frequent referee for Physical Review Letter, Physics of Plasmas, Nuclear Instruments and Methods for Physics Research, Nuclear Fusion, Plasma Physics and Controlled Fusion, Radiation Measurements, and European Physics Journal. He is a member of the American Physical Society (Divisions of Plasma Physics and Nuclear Physics).




Applied nuclear physics, Department of Neutron Research, Uppsala University, Sweden, 1998.
(Thesis: "Instrumentation for fusion neutron measurements and experimentation at JET")

See the thesis defense on the Swedish news.



Engineering Physics, Department of Technology, Uppsala University, Sweden 1992.
(Field of specialization: Radiation Sciences)


Selected Bibliography


J.A. Frenje, C.K. Li, F.H. Séguin, D.T. Casey, R.D. Petrasso, D.P. McNabb, P. Navratil, S. Quaglioni, T.C. Sangster, V. Yu Glebov and D.D. Meyerhofer, “Measurements of the differential cross section for the elastic n-3H and n-2H scattering at 14.1 MeV by using an Inertial Confinement Fusion (ICF) facility”, Phys. Rev. Letters 107, 122502 (2011).
J.A. Frenje, , D.T. Casey, C.K. Li, F.H. Séguin, R.D. Petrasso, V. Yu Glebov, P.B. Radha, T.C. Sangster, D.D. Meyerhofer, S.P. Hatchett, S.W. Haan, C.J. Cerjan, O.L. Landen, K.A. Fletcher, and R.J. Leeper, “Probing high areal-density (ρR) cryogenic DT implosions using down scattered neutron spectra measured by the Magnetic Recoil Spectrometer (MRS)”, Phys. Plasmas 17, 056311 (2010).
J.A. Frenje, C.K. Li, J.R. Rygg, F.H. Séguin, D.T. Casey, R.D. Petrasso, J. Delettrez, V.Yu. Glebov, T.C. Sangster, O. Landen and S. Hatchett, “Diagnosing ablator ρR and ρR asymmetries in capsule implosions using charged-particle spectrometry at the National Ignition Facility”, Phys. Plasmas 16, 022702 (2009).
J.A. Frenje, D.T. Casey, C.K. Li, J.R. Rygg, F.H. Séguin, R.D. Petrasso, V.Yu Glebov, D.D. Meyerhofer, T.C. Sangster, S. Hatchett, S. Haan, C. Cerjan, O. Landen, M. Moran, P. Song, D.C. Wilson and R.J. Leeper, “First measurements of the absolute neutron spectrum using the magnetic recoil spectrometer at OMEGA”, Rev. Sci. Instrum. 79 10E502 (2008).
J.A. Frenje, C.K. Li, F.H. Séguin, J. Deciantis, S. Kurebayashi, R. Rygg, R.D. Petrasso, J. Delettrez, V.Yu. Glebov, C. Stoeckl, F.J. Marshall, D.D. Meyerhofer, T.C. Sangster, V.A. Smalyuk and J.M. Soures, “Measuring shock-bang timing and ρR evolution of D3He implosions at OMEGA”, Phys. Plasmas 11, 2798 (2004).






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