Ofer Cohen headshot

Ofer Cohen

Associate Professor

College of Sciences
(978) 934-4913
Olney Hall - 101A


Computational plasma physics, Computational methods, Magnetohydrodynamics

Research Interests

Heliophysics, Exoplanets, Stellar astrophysics, Space weather, Planetary atmospheres


  • Ph D: Space and Planetary Physics, (2008), University of Michigan, Department of Atmospheric, Oceanic, & Space Sciences - Ann Arbor, MI
    Dissertation/Thesis Title: The Solar Corona through Numerical Eyes
  • MS, (2002), Tel-Aviv University, Department of Geophysics & Planetary Sciences - Tel- Aviv, Israel
  • BS, (2000), Tel-Aviv University, Department of Geophysics & Planetary Sciences - Tel- Aviv, Israel


During his graduate studies Professor Cohen developed a cutting-edge numerical model to study the solar corona and the solar wind. This model has been also used as a prototype for a forecasting system to predict space weather and its impact on satellites, astronauts and space-born technology.
After completing his PhD., Professor Cohen moved to the Harvard-Smithsonian center for astrophysics as an NSF fellow. He continued to work on studies of the solar corona, but at the same time began to implement his solar model of other stars in order to study stellar astrophysics problems, such as the spindown and mass-loss rates of low-mass stars. These parameters are very important for stellar evolution, but they cannot be directly measured. Thus, Professor Cohen’s modeling work on stellar winds has provided a significant advancement.
In addition, Professor Cohen has been implementing models that have been developed to connect the Earth and solar system objects to the study of exoplanets. This approach provided a much more realistic view on exoplanets and their characteristics.
Professor Cohen has established himself as an interdisciplinary researcher who works on many topics falling within the range of planetary science, heliophysics, solar physics and astrophysics. He has served as a scientific reviewer in many review panels of NASA and the NSF, a long list of scientific journals and graduate student and postdoc review panels

Selected Awards and Honors

  • NASA Postdoc Fellowship (NPP) (2016) - NASA
  • NSF Postdoctoral Fellow (2010) - Harvard-Smithsonian CfA

Selected Publications

  • Alvarado-Gomez, J.D., Garraffo, C., Drake, Jeremy J. Brown, Benjamin P., ., Oishi, J.S., Moschou, S., Cohen, O. (2018). Breezing through the space environment of Barnard's Star b. Astroph. J., submitted.
  • Airapetian, V.~S., ., Danchi, W.~C., ., Dong, C.~F., ., Rugheimer, S., Mlynczak, M., Stevenson, K.~B., ., Henning, W.~G., ., Grenfell, J.~L., ., Jin, M., Glocer, A., Gronoff, G., Lynch, B., Johnstone, C., Lueftinger, T., Guedel, M., Kobayashi, K., Fahrenbach, A., Hallinan, G., Stamenkovic, V., Cohen, O., Kuang, W., van der Holst, B., Manchester, C., Zank, G., Verkhoglyadova, O., Sojka, J., Maehara, H., Notsu, Y., Yamashiki, Y., France, K., Lopez Puertas, M., Funke, B., Jackman, C., Kay, C., Leisawitz, D., Alexander, D. (2018). Life Beyond the Solar System: Space Weather and Its Impact on Habitable Worlds. ArXiv e-prints, arXiv:1801.07333.
  • Moschou, S., Drake, J.J., Cohen, O., Alvarado-Gomez, J.D., Garraffo, C., Fraschetti, F. (2018). Stellar CME-flare relation: What do historic observations reveal? Astroph. J., submitted.
  • Fraschetti, F., Drake, J.J., Alvarado-Gomez, J.D., Moschou, S., Garraffo, C., Cohen, O. (2018). Stellar energetic particles in the magnetically turbulent habitable zones of TRAPPIST-1-like planetary systems. Astroph. J., in press.
  • Garraffo, C., Drake, J.~J., ., Dotter, A., Choi, J., Burke, D.~J., ., Moschou, S.~P., ., Alvarado-G\'omez,J.~D., ., Kashyap, V.~L., ., Cohen, O. (2018). The Revolution Revolution: Magnetic Morphology Driven Spin-down. Astroph. J., 862 90.
  • Al Shidi, Q., Cohen, O., Song, P., Tu, J. (2018). Time-Dependent Two-Fluid Magnetohydrodynamic Model and Simulation of the Chromosphere. Sol. Phys., submitted.
  • Cohen, O., Moschou, S., Glocer, A., Sokolov, I.V., Mazeh, T., Drake, J.J., Garraffo, C., Alvarado-G\'omez, J.~D., . (2018). Exoplanet Modulation of Stellar Coronal Radio Emission. Astron. J., 156 202.
  • Moschou, S., Sokolov, I., Cohen, O., Drake, J.J., Borovikov, D., Kasper, J.C., Alvarado-Gomez, J.D., Garraffo, C. (2018). Synthetic Radio Imaging for Quiescent and CME-flare Scenarios. Astroph. J., 867 51.
  • Alvarado-G\'omez, Juli\'an D., ., Drake, J.J., Cohen, O., Moschou, S.P., Garraffo, C. (2018). Suppression of Coronal Mass Ejections in Active Stars by an Overlying Large-scale Magnetic Field: A Numerical Study. Astroph. J., 862 93.
  • Garraffo, C., Drake, J.~J., ., Alvarado-Gomez, J.~D., ., Moschou, S.~P., ., Cohen, O. (2018). The Magnetic Nature of the Cataclysmic Variable Period Gap. ArXiv e-prints, arXiv:1808.09450.
  • Oran, R., Weiss, B.P., Cohen, O. (2018). Were chondrites magnetized by the early solar wind? Earth and Planetary Science Letters, 492 222-231.
  • Cohen, O., Glocer, A., Garraffo, C., Drake, J.J., Bell, J.M. (2018). Energy Dissipation in the Upper Atmospheres of TRAPPIST-1 Planets. Astroph. J., 856 L11.
  • Pognan, Q., Garraffo, C., Cohen, O., Drake, J.J. (2018). The Solar Wind Environment in Time. Astroph. J., 856 53.
  • Alvarado-G\'omez, Juli\'an D., ., Hussain, Gaitee A.~J., ., Drake, J.J., Donati, Jean-Fran\ccois, ., Sanz- Forcada, J., Stelzer, B., Cohen, O., Amazo-G\'omez, Eliana M., ., Grunhut, J.H., Garraffo, C., Moschou, S.P., Silvester, J., Oksala, M.E. (2018). Far beyond the Sun - I. The beating magnetic heart in Horologium. MNRAS, 473 4326-4338.
  • Nikolov, N., Sing, D.~K., ., Goyal, J., Henry, G.~W., ., Wakeford, H.~R., ., Evans, T.~M., ., L\'opez-Morales, M., ., Garc\'\ia Mu\~noz, A., ., Ben-Jaffel, L., Sanz- Forcada, J., Ballester, G.~E., ., Kataria, T., Barstow, J.~K., ., Bourrier, V., Buchhave, L.~A., ., Cohen, O., Deming, D., Ehrenreich, D., Knutson, H., Lavvas, P., Lecavelier des Etangs, A., ., Lewis, N.~K., ., Mandell, A.~M., ., Williamson, M.~H., . (2018). Hubble PanCET: an isothermal day-side atmosphere for the bloated gas- giant HAT-P-32Ab. MNRAS, 474 1705-1717.
  • Fraschetti, F., Drake, J.~J., ., Cohen, O., Garraffo, C. (2018). Mottled Protoplanetary Disk Ionization by Magnetically Channeled T Tauri Star Energetic Particles. Astroph. J., 853 112.
  • Moschou, S., Drake, J.J., Cohen, O., Alvarado-Gomez, J.D., Garraffo, C. (2017). A Monster CME Obscuring a Demon Star Flare. Astroph. J., 850 191.
  • Cohen, O., Yadav, R., Garraffo, C., Saar, S.~H., ., Wolk, S.~J., ., Kashyap, V.~L., ., Drake, J.~J., ., Pillitteri, I. (2017). Giant Coronal Loops Dominate the Quiescent X-Ray Emission in Rapidly Rotating M Stars. Astroph. J., 834 14.
  • Garcia-Sage, K., Glocer, A., Drake, J.~J., ., Gronoff, G., Cohen, O. (2017). On the Magnetic Protection of the Atmosphere of Proxima Centauri b. Astroph. J., 844 L13.
  • Garraffo, C., Drake, J.J., Cohen, O., Alvarado-G\'omez, Julian D., ., Moschou, S.P. (2017). The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets. Astroph. J., 843 L33.
  • Evans, T.M., Sing, D.K., Kataria, T., Goyal, J., Nikolov, N., Wakeford, H.R., Deming, D., Marley, M.S., Amundsen, D.S., Ballester, G.E., Barstow, J.K., Ben- Jaffel, L., Bourrier, V., Buchhave, L.A., Cohen, O., Ehrenreich, D., Garc\'\ia Mu\~noz, Antonio, ., Henry, G.W., Knutson, H., Lavvas, P., Lecavelier Des Etangs, Alain, ., Lewis, N.K., L\'opez-Morales, Mercedes, ., Mandell, A.M., Sanz-Forcada, J., Tremblin, P., Lupu, R. (2017). An ultrahot gas-giant exoplanet with a stratosphere. Nature, 548 58-61.
  • Dong, C., Lingam, M., Ma, Y., Cohen, O. (2017). Is Proxima Centauri b Habitable? A Study of Atmospheric Loss. Astroph. J., 837 L26.
  • Cohen, O. (2017). A Comparison between Physics-based and Polytropic MHD Models for Stellar Coronae and Stellar Winds of Solar Analogs. Astroph. J., 835 220.

Selected Contracts, Fellowships, Grants and Sponsored Research

  • Geophysically Relevant Prediction of Solar Cycle 25 (2016), Grant -
    Cohen, O.
  • The Heliosphere in Time: Scaling Heliospheric Parameters with Stellar Evolution of Solar Analogs and Studying Heliospheric Consequences of Young Active Suns (2016), Grant - NASA LWS
    Cohen, O. (Principal)
  • The Living, Breathing Planet (2015), Grant - NASA NEXSS
    Cohen, O.
  • Can Exoplanets Around Red Dwarfs Maintain Habitable Atmospheres? (2014), Grant - SI Competitive Grants Program for Science
    Cohen, O. (Co-Principal), Drake, J. (Principal)
  • Lessons from Mars: Are Habitable Atmospheres on Planets around M Dwarfs Viable? (2014), Grant - The Smithsonian Consortia
    Cohen, O. (Co-Principal), Drake, J.
  • 3D MHD Modeling of Stellar Coronae (2012), Grant - Chandra theory program cycle 13
    Cohen, O. (Principal)
  • The Faint Young sun Paradox (2012), Grant - The Smithsonian Consortia
    Cohen, O. (Co-Principal), Latham, D. (Principal)
  • Life and the Cosmos: Building the Consortium (2011), Grant - The Smithsonian Consortia
    Cohen, O. (Co-Principal), Drake, J. (Principal)
  • The Role of Coronal Mass Ejections in Reversal the Open Magnetic Flux of the Sun (2008), Grant - National Science Foundation
    Cohen, O. (Principal)