Bio


Ken Hara is an Assistant Professor of Aeronautics and Astronautics at Stanford University. He received a Ph.D. in Aerospace Engineering and a Graduate Certificate in Plasma Science and Engineering from the University of Michigan, and B.S. and M.S. in Aeronautics and Astronautics from the University of Tokyo. He was a Visiting Research Physicist at Princeton Plasma Physics Laboratory as a Japan Society for the Promotion of Science Postdoctoral Fellow. Professor Hara’s research interests include electric propulsion, low temperature plasmas, plasma physics (plasma-wall interactions, plasma-wave interactions), data-driven modeling, rarefied gas flows, and computational fluid and plasma dynamics. He is a recipient of the Air Force Young Investigator Program Award, the Department of Energy Early Career Award, and the Office of Naval Research Young Investigator Program Award.

Academic Appointments


Honors & Awards


  • Young Investigator Program (YIP) Award, Office of Naval Research (2021)
  • Kuriki Award for Young Professionals, Electric Rocket Propulsion Society (2019)
  • Early Career Research Program Award, Department of Energy (2018)
  • JPL Summer Faculty Research Program, Jet Propulsion Laboratory, Caltech (2017)
  • Young Investigator Research Program (YIP) Award, Air Force Office of Scientific Research (2017)
  • Postdoctoral Fellowship, Japan Society for the Promotion of Science (2015-2016)
  • Nuclear and Plasma Sciences Society Graduate Scholarship Award, IEEE (2015)
  • Outstanding Student Paper Award, 41st IEEE International Conference on Plasma Science (2014)
  • Richard F. and Eleanor A. Towner Prize for Distinguished Academic Achievement, College of Engineering, University of Michigan (2013)

Professional Education


  • PhD, University of Michigan, Aerospace Engineering (2015)
  • MS, University of Tokyo, Aeronautics and Astronautics (2010)
  • BS, University of Tokyo, Aeronautics and Astronautics (2008)

Stanford Advisees


All Publications


  • Estimation of plasma properties using an extended Kalman filter with plasma global models JOURNAL OF PHYSICS D-APPLIED PHYSICS Greve, C. M., Hara, K. 2022; 55 (25)
  • Full fluid moment modeling of rotating spokes in Penning-type configuration PLASMA SOURCES SCIENCE & TECHNOLOGY Mansour, A. R., Hara, K. 2022; 31 (5)
  • Mutually guided light and particle beam propagation. Scientific reports Castillo, A. M., Kumar, P., Limbach, C. M., Hara, K. 2022; 12 (1): 4810

    Abstract

    The polarizability of atoms and molecules gives rise to optical forces that trap particles and a refractive index that guides light beams, potentially leading to a self-guided laser and particle beam propagation. In this paper, the mutual interactions between an expanding particle beam and a diffracting light beam are investigated using an axisymmetric particle-light coupled simulation. The nonlinear coupling between particles and photons is dependent on the particle beam radius, particle density, particle velocity and temperature, polarizability, light beam waist, light frequency (with respect to the resonance frequency), and light intensity. The computational results show that the maximum propagation distance is achieved when the waveguiding effect is optimized to single-mode operation. The application of the coupled beam propagation as a space propulsion system is discussed.

    View details for DOI 10.1038/s41598-022-08802-z

    View details for PubMedID 35314753

  • Characterization of hollow cathode plasma turbulence using coherent Thomson scattering JOURNAL OF APPLIED PHYSICS Tsikata, S., Hara, K., Mazouffre, S. 2021; 130 (24)

    View details for DOI 10.1063/5.0071650

    View details for Web of Science ID 000739055500001

  • Effects of multiply charged ions on microturbulence-driven electron transport in partially magnetized plasmas JOURNAL OF APPLIED PHYSICS Kumar, P., Tsikata, S., Hara, K. 2021; 130 (17)

    View details for DOI 10.1063/5.0067305

    View details for Web of Science ID 000716462300004

  • Real-time state estimation of low-frequency plasma oscillations in Hall effect thrusters PHYSICS OF PLASMAS Greve, C. M., Majji, M., Hara, K. 2021; 28 (9)

    View details for DOI 10.1063/5.0057751

    View details for Web of Science ID 000747761200002

  • 2D radial-azimuthal particle-in-cell benchmark for E x B discharges PLASMA SOURCES SCIENCE & TECHNOLOGY Villafana, W., Petronio, F., Denig, A. C., Jimenez, M. J., Eremin, D., Garrigues, L., Taccogna, F., Alvarez-Laguna, A., Boeuf, J. P., Bourdon, A., Chabert, P., Charoy, T., Cuenot, B., Hara, K., Pechereau, F., Smolyakov, A., Sydorenko, D., Tavant, A., Vermorel, O. 2021; 30 (7)
  • Application of State Estimation Methods to Low-Temperature Plasma Dynamics Greve, C., Hara, K., Majji, M., IEEE IEEE. 2021: 1-5
  • Nonlinear dynamics of coupled light and particle beam propagation Physical Review A Kumar, P., Kuldinow, D., Castillo, A., Gerakis, A., Hara, K. 2021; 103 (04)
  • Physics of ExB discharges relevant to plasma propulsion and similar technologies PHYSICS OF PLASMAS Kaganovich, I. D., Smolyakov, A., Raitses, Y., Ahedo, E., Mikellides, I. G., Jorns, B., Taccogna, F., Gueroult, R., Tsikata, S., Bourdon, A., Boeuf, J., Keidar, M., Powis, A., Merino, M., Cappelli, M., Hara, K., Carlsson, J. A., Fisch, N. J., Chabert, P., Schweigert, I., Lafleur, T., Matyash, K., Khrabrov, A. V., Boswell, R. W., Fruchtman, A. 2020; 27 (12)

    View details for DOI 10.1063/5.0010135

    View details for Web of Science ID 000600206100001

  • Full fluid moment model for low temperature magnetized plasmas PHYSICS OF PLASMAS Sahu, R., Mansour, A. R., Hara, K. 2020; 27 (11)

    View details for DOI 10.1063/5.0021474

    View details for Web of Science ID 000590777500001

  • Non-monotonic double layers and electron two-stream instabilities resulting from intermittent ion acoustic wave growth PHYSICS OF PLASMAS Vazsonyi, A. R., Hara, K., Boyd, I. D. 2020; 27 (11)

    View details for DOI 10.1063/5.0019729

    View details for Web of Science ID 000595631700001

  • Cross-field electron diffusion due to the coupling of drift-driven microinstabilities PHYSICAL REVIEW E Hara, K., Tsikata, S. 2020; 102 (2)
  • Cross-field electron diffusion due to the coupling of drift-driven microinstabilities. Physical review. E Hara, K., Tsikata, S. 2020; 102 (2-1): 023202

    Abstract

    In this paper, the nonlinear interaction between kinetic instabilities driven by multiple ion beams and magnetized electrons is investigated. Electron diffusion across magnetic field lines is enhanced by the coupling of plasma instabilities. A two-dimensional collisionless particle-in-cell simulation is performed accounting for singly and doubly charged ions in a cross-field configuration. Consistent with prior linear kinetic theory analysis and observations from coherent Thomson scattering experiments, the present simulations identify an ion-ion two-stream instability due to multiply charged ions (flowing in the direction parallel to the applied electric field) which coexists with the electron cyclotron drift instability (propagating perpendicular to the applied electric field and parallel to the E×B drift). Small-scale fluctuations due to the coupling of these naturally driven kinetic modes are found to be a mechanism that can enhance cross-field electron transport and contribute to the broadening of the ion velocity distribution functions.

    View details for DOI 10.1103/PhysRevE.102.023202

    View details for PubMedID 32942351

  • Self-organized standing waves generated by AC-driven electron cyclotron drift instabilities APPLIED PHYSICS LETTERS DesJardin, I. M., Hara, K., Tsikata, S. 2019; 115 (23)

    View details for DOI 10.1063/1.5131019

    View details for Web of Science ID 000504304400030

  • Two-dimensional hybrid-direct kinetic simulation of a Hall thruster discharge plasma PHYSICS OF PLASMAS Raisanen, A. L., Hara, K., Boyd, I. D. 2019; 26 (12)

    View details for DOI 10.1063/1.5122290

    View details for Web of Science ID 000505578200008

  • 2D axial-azimuthal particle-in-cell benchmark for low-temperature partially magnetized plasmas PLASMA SOURCES SCIENCE & TECHNOLOGY Charoy, T., Boeuf, J. P., Bourdon, A., Carlsson, J. A., Chabert, P., Cuenot, B., Eremin, D., Garrigues, L., Hara, K., Kaganovich, I. D., Powis, A. T., Smolyakov, A., Sydorenko, D., Tavant, A., Vermorel, O., Villafana, W. 2019; 28 (10)
  • A data-driven approach to model calibration for nonlinear dynamical systems JOURNAL OF APPLIED PHYSICS Greve, C. M., Hara, K., Martin, R. S., Eckhardt, D. Q., Koo, J. W. 2019; 125 (24)

    View details for DOI 10.1063/1.5085780

    View details for Web of Science ID 000474439600008

  • Ion kinetics and nonlinear saturation of current-driven instabilities relevant to hollow cathode plasmas PLASMA SOURCES SCIENCE & TECHNOLOGY Hara, K., Treece, C. 2019; 28 (5)
  • An overview of discharge plasma modeling for Hall effect thrusters PLASMA SOURCES SCIENCE & TECHNOLOGY Hara, K. 2019; 28 (4)
  • Spatiotemporal data fusion and manifold reconstruction in Hall thrusters PLASMA SOURCES SCIENCE & TECHNOLOGY Eckhardt, D., Koo, J., Martin, R., Holmes, M., Hara, K. 2019; 28 (4)
  • Multispecies plasma fluid simulation for carbon arc discharge JOURNAL OF PHYSICS D-APPLIED PHYSICS Mansour, A. R., Hara, K. 2019; 52 (10)
  • Non-oscillatory quasineutral fluid model of cross-field discharge plasmas PHYSICS OF PLASMAS Hara, K. 2018; 25 (12)

    View details for DOI 10.1063/1.5055750

    View details for Web of Science ID 000454905100069

  • Test cases for grid-based direct kinetic modeling of plasma flows PLASMA SOURCES SCIENCE & TECHNOLOGY Hara, K., Hanquist, K. 2018; 27 (6)
  • Amplification due to two-stream instability of self-electric and magnetic fields of an ion beam propagating in background plasma Tokluoglu, E. K., Kaganovich, I. D., Carlsson, J. A., Hara, K., Startsev, E. A. AMER INST PHYSICS. 2018

    View details for DOI 10.1063/1.5038878

    View details for Web of Science ID 000433961800024

  • Numerical analysis of azimuthal rotating spokes in a crossed-field discharge plasma PLASMA SOURCES SCIENCE & TECHNOLOGY Kawashima, R., Hara, K., Komurasaki, K. 2018; 27 (3)
  • On limitations of laser-induced fluorescence diagnostics for xenon ion velocity distribution function measurements in Hall thrusters PHYSICS OF PLASMAS Romadanov, I., Raitses, Y., Diallo, A., Hara, K., Kaganovich, I. D., Smolyakov, A. 2018; 25 (3)

    View details for DOI 10.1063/1.5020749

    View details for Web of Science ID 000428987800077

  • Generation of forerunner electron beam during interaction of ion beam pulse with plasma Hara, K., Kaganovich, I. D., Startsev, E. A. AMER INST PHYSICS. 2018

    View details for DOI 10.1063/1.5002688

    View details for Web of Science ID 000424021700015

  • Kinetic simulations of ladder climbing by electron plasma waves PHYSICAL REVIEW E Hara, K., Barth, I., Kaminski, E., Dodin, I. Y., Fisch, N. J. 2017; 95 (5): 053212

    Abstract

    The energy of plasma waves can be moved up and down the spectrum using chirped modulations of plasma parameters, which can be driven by external fields. Depending on whether the wave spectrum is discrete (bounded plasma) or continuous (boundless plasma), this phenomenon is called ladder climbing (LC) or autoresonant acceleration of plasmons. It was first proposed by Barth et al. [Phys. Rev. Lett. 115, 075001 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.075001] based on a linear fluid model. In this paper, LC of electron plasma waves is investigated using fully nonlinear Vlasov-Poisson simulations of collisionless bounded plasma. It is shown that, in agreement with the basic theory, plasmons survive substantial transformations of the spectrum and are destroyed only when their wave numbers become large enough to trigger Landau damping. Since nonlinear effects decrease the damping rate, LC is even more efficient when practiced on structures like quasiperiodic Bernstein-Greene-Kruskal (BGK) waves rather than on Langmuir waves per se.

    View details for DOI 10.1103/PhysRevE.95.053212

    View details for Web of Science ID 000402019600015

    View details for PubMedID 28618641

  • Detailed modeling of electron emission for transpiration cooling of hypersonic vehicles JOURNAL OF APPLIED PHYSICS Hanquist, K. M., Hara, K., Boyd, I. D. 2017; 121 (5)

    View details for DOI 10.1063/1.4974961

    View details for Web of Science ID 000394345700008

  • AMPLIFICATION DUE TO THE TWO-STREAM INSTABILITY OF SELF-ELECTRIC AND MAGNETIC FIELDS OF AN ION OR ELECTRON BEAM PROPAGATING IN BACKGROUND PLASMA Tokluoglu, E. K., Kaganovich, I. D., Carlsson, J. A., Hara, K., Powis, A., IEEE IEEE. 2017
  • ADVANCED MAGNETO-GAS-KINETIC SCHEME FOR MHD: ANALYSIS AND COMPARISON TO EXISTING MODELS Anderson, S. E., Hara, K., Girimaji, S. S., IEEE IEEE. 2017
  • NUMERICAL MODELING OF ROTATING SPOKES IN HALL THRUSTER DISCHARGE PLASMA Kawashima, R., Hara, K., IEEE IEEE. 2017
  • Electron acceleration due to the interaction between a neutralized ion beam and background plasma Hara, K., Kaganovich, I. D., IEEE IEEE. 2017
  • Quantitative study of the trapped particle bunching instability in Langmuir waves PHYSICS OF PLASMAS Hara, K., Chapman, T., Banks, J. W., Brunner, S., Joseph, I., Berger, R. L., Boyd, I. D. 2015; 22 (2)

    View details for DOI 10.1063/1.4906884

    View details for Web of Science ID 000350552000021

  • Perturbation analysis of ionization oscillations in Hall effect thrusters PHYSICS OF PLASMAS Hara, K., Sekerak, M. J., Boyd, I. D., Gallimore, A. D. 2014; 21 (12)

    View details for DOI 10.1063/1.4903843

    View details for Web of Science ID 000347162700007

  • Mode transition of a Hall thruster discharge plasma JOURNAL OF APPLIED PHYSICS Hara, K., Sekerak, M. J., Boyd, I. D., Gallimore, A. D. 2014; 115 (20)

    View details for DOI 10.1063/1.4879896

    View details for Web of Science ID 000337143500016

  • One-dimensional hybrid-direct kinetic simulation of the discharge plasma in a Hall thruster PHYSICS OF PLASMAS Hara, K., Boyd, I. D., Kolobov, V. I. 2012; 19 (11)

    View details for DOI 10.1063/1.4768430

    View details for Web of Science ID 000312033700072