Prayash Pyakurel

Prayash Pyakurel, Ph.D.

Assistant Research Physicist

Space Sciences Laboratory, University of California, Berkeley

Plasma physicist. I combine spacecraft observations, kinetic particle-in-cell simulations and theory to determine when magnetic reconnection occurs, how fast it proceeds, and how it converts and partitions energy across scales.

Pyakurel Plasma Lab Publications pspyakurel@berkeley.edu
21peer-reviewed papers
7as first author, including two in PRL
$0.73MNASA funding as principal investigator
15invited talks and seminars

About

Magnetic reconnection, from simulations to spacecraft

I am an Assistant Research Physicist at the Space Sciences Laboratory of the University of California, Berkeley, and adjunct faculty in the Department of Physics and Astronomy at James Madison University.

My research uses three approaches together: spacecraft observations and event identification (NASA's Magnetospheric Multiscale mission and Parker Solar Probe), first-principles kinetic particle-in-cell (PIC) simulations, and theory, including wave, instability and kinetic damping analysis. Most of my work is on electron-only reconnection in turbulence, where thin current sheets reconnect without the ions taking part, and on reconnection in the outer heliosphere with pickup ions.

I received my Ph.D. in Physics from the University of Delaware in 2019 and my B.S. in Physics and Mathematics from Truman State University. I was a postdoctoral scholar at Berkeley from 2019 to 2023. I have led NASA-funded projects as principal investigator; my total external research funding is $899,697.

Positions

  • 2023 –Assistant Research PhysicistSpace Sciences Laboratory, UC Berkeley
  • 2024 –Adjunct Faculty, Physics and AstronomyJames Madison University, Harrisonburg, VA
  • 2019 – 2023Postdoctoral ScholarSpace Sciences Laboratory, UC Berkeley
  • 2014 – 2019Graduate Research AssistantUniversity of Delaware

Education

  • 2019Ph.D., PhysicsUniversity of Delaware
  • 2010B.S., Physics and B.S., MathematicsTruman State University, Kirksville, MO

Research

What I work on

Kinetic particle-in-cell simulations

Kinetic PIC and hybrid-PIC simulations of collisionless reconnection, compared directly with spacecraft data. The processes I study:

  • Transition from ion-coupled to electron-only reconnectionSystem size controls whether the ions are decoupled, partially coupled or fully coupled to reconnection. Electron-only reconnection is much faster than ion-coupled reconnection.PoP 2019
  • 3D electron-only reconnection with a finite X-lineWhen the X-line has finite length, mass flows along it; the inflow speed, the parallel electric field and the reconnection rate all double compared with 2D.PRL 2021
  • Reconnection rate modelsModeling the rate of electron-only reconnection.Comm. Phys. 2025
  • Reconnection with pickup ionsOuter-heliosphere conditions: pickup-ion shell distributions stay quasi-stable in the exhaust and change the reconnection rate and exhaust structure. Next: parameter sweeps in current-sheet thickness and β, and shell versus ring distributions.ApJ 2025
  • Reconnection and turbulenceReconnection viewed as turbulence, the effect of a guide field, and energy transfer between the two.PoP 2020 · PRE 2021 · PoP 2023
  • Onset signatures and kinetic dampingKinetic Alfvén waves launched at reconnection onset propagate super-Alfvénically; which wave modes survive over observable distances and which are damped.JGR 2018
  • Energy conversionWhat controls the spatial structure and sign of the energy conversion parameter j·E′.

Spacecraft observations: MMS and Parker Solar Probe

Event identification and analysis with MMS near Earth and Parker Solar Probe near the Sun. Current work:

  • MMS · Survey of electron-only reconnectionA survey of magnetosheath current sheets across plasma conditions, to find signatures that identify electron-only reconnection even when only one electron jet is seen, and to measure its occurrence, rate and energy partition.in preparation
  • MMS · Dependence on plasma β and magnetic shearTheory and observations of how β and shear control electron-only reconnection, and the conditions for its onset.ApJ 2026
  • MMS · Reconnection inside a magnetopause exhaustLarge guide field electron-only reconnection embedded in a large-scale magnetopause exhaust, with electron jets opposite to the large-scale X-line: nested reconnection across electron and ion scales.PRL 2025
  • MMS · Electron-scale structureElectron inflows that vary over a few electron inertial lengths, compared quantitatively with PIC simulations; X-line lengths from multi-spacecraft measurements.ApJ 2023
  • PSP · Reconnection near the Sun (new)Just getting started: reconnection sites in heliospheric current sheet crossings, and proton heating in the exhausts (parallel versus perpendicular).ongoing · builds on A&A 2021, GRL 2022

Teaching resource

Pyakurel Plasma Lab

An open, interactive course on plasma physics and magnetic reconnection for students, built step by step from the basics to the research frontier, with a simulation code you can run on your own laptop.

  • Plasma basics, frozen-in flux, the Harris sheet and the Sweet–Parker model
  • X-points, islands, the flux function and the reconnection rate, with rotatable 3D figures
  • splmhd: a readable resistive-MHD code in Python, in Cartesian or spherical geometry, 2D or 3D, with a parameter builder, a live monitor and every equation explained
Open the Plasma Lab → The simulation code
Plasma basicsWhat a plasma is, and how particles move in fields Magnetic reconnectionFrom frozen-in flux to Sweet–Parker Advanced topicsPotentials, islands, Ohm's law, resistive MHD Run a simulationDownload splmhd and watch reconnection live

Publications

Articles

  1. The Dependence of Electron-only Magnetic Reconnection on Plasma Beta and Magnetic Shear: Theory and Observationsfirst author
    Pyakurel, P. S., Mallet, A., Phan, T. D., Swisdak, M., Øieroset, M., & Burch, J. L.
    The Astrophysical Journal (2026) · doi:10.3847/1538-4357/ae5e57
  2. The Enhancement of Ion Heating in Kinetic, Anti-Parallel Reconnection in the Presence of a Flow Shear
    Haggerty, C. C., Sikorski, D., Shay, M. A., Phan, T. D., Cassak, P. A., Murtas, G., & Pyakurel, P. S.
    The Astrophysical Journal (2025) · doi:10.3847/1538-4357/ae2014
  3. Kinetic Simulation of Magnetic Reconnection with Pickup Ions: Shell Stability and Reconnection Rate Analysisfirst author
    Pyakurel, P. S., Swisdak, M., Eriksson, S., Shrestha, B. L., Liu, Y.-H., TenBarge, J. M., Shay, M. A., & Phan, T. D.
    The Astrophysical Journal (2025) · doi:10.3847/1538-4357/ade3db
  4. Detection of Large Guide Field Electron-only Reconnection in a Filamentary Current Sheet Immersed in a Large-scale Magnetopause Reconnection Exhaustfirst authorhighlight
    Pyakurel, P. S., Phan, T. D., Øieroset, M., Drake, J. F., Shay, M. A., Mallet, A., Stawarz, J., Wang, S., Oka, M., Genestreti, K. J., Ahmadi, N., Burch, J. L., Torbert, R. B., Ergun, R. E., Gershman, D. J., Giles, B. L., & Strangeway, R. J.
    Physical Review Letters (2025) · doi:10.1103/PhysRevLett.134.115201
  5. Modeling Electron-only Magnetic Reconnection Ratehighlight
    Liu, Y.-H., Pyakurel, P. S., Li, X., et al.
    Communications Physics (2025) · doi:10.1038/s42005-025-02034-z
  6. New Insights on the High Reconnection Rate and the Diminishment of Ion Outflow
    Fan, C.-Y., Wang, S., Zhou, X.-Z., Lu, S., Lu, Q., Pyakurel, P. S., Zong, Q., & Liu, Z.-Y.
    Geophysical Research Letters (2025) · doi:10.1029/2024GL113889
  7. In-situ Observations of the Magnetothermodynamic Evolution of Electron-only Reconnectionhighlight
    Payne, D., Swisdak, M., Eastwood, J., Drake, J. F., Pyakurel, P. S., & Shuster, J.
    Communications Physics (2025) · doi:10.1038/s42005-025-01948-y
  8. Energy Dissipation in Electron-only Reconnection
    Roy, S., Bandyopadhyay, R., Matthaeus, W. H., & Pyakurel, P. S.
    The Astrophysical Journal (2024) · doi:10.3847/1538-4357/ad2769
  9. On the Short-scale Spatial Variability of Electron Inflows in Electron-only Magnetic Reconnection in the Turbulent Magnetosheath Observed by MMSfirst author
    Pyakurel, P. S., Phan, T. D., Drake, J. F., Shay, M. A., Øieroset, M., Haggerty, C. C., Stawarz, J., Burch, J. L., Ergun, R. E., Gershman, D. J., Giles, B. L., Torbert, R. B., Strangeway, R. J., & Russell, C. T.
    The Astrophysical Journal (2023) · doi:10.3847/1538-4357/acb6f1
  10. Bulletin of the American Astronomical Society 55
    Eriksson, S., Pyakurel, P., Mallet, A., Swisdak, M., et al.
    (2023) · doi:10.3847/25c2cfeb.f5c0635b
  11. Effect of a Guide Field on the Turbulence-like Properties of Magnetic Reconnection
    Adhikari, S., Shay, M. A., Parashar, T. N., Matthaeus, W. H., Pyakurel, P. S., Stawarz, J. E., & Eastwood, J. P.
    Physics of Plasmas (2023) · doi:10.1063/5.0150929
  12. Turbulence-driven Magnetic Reconnection and the Magnetic Correlation Length: Observations from Magnetospheric Multiscale in Earth's Magnetosheath
    Stawarz, J. E., Eastwood, J. P., Phan, T. D., Gingell, I. L., Pyakurel, P. S., Shay, M. A., Robertson, S. L., Russell, C. T., & Le Contel, O.
    Physics of Plasmas (2022) · doi:10.1063/5.0071106
  13. Parker Solar Probe Observations of Solar Wind Energetic Proton Beams Produced by Magnetic Reconnection in the Near-Sun Heliospheric Current Sheet
    Phan, T. D., Verniero, J. L., Larson, D., Lavraud, B., Eastwood, J. P., Drake, J. F., Bale, S. D., et al., Pyakurel, P. S., et al.
    Geophysical Research Letters (2022) · doi:10.1029/2021GL096986
  14. Faster Form of Electron Magnetic Reconnection with a Finite Length X-Linefirst authorhighlight
    Pyakurel, P. S., Shay, M. A., Drake, J. F., Phan, T. D., Cassak, P. A., & Verniero, J. L.
    Physical Review Letters (2021) · doi:10.1103/PhysRevLett.127.155101
  15. Spatial Evolution of Magnetic Reconnection Diffusion Region Structures with Distance from the X-line
    Øieroset, M., Phan, T. D., Ergun, R., Ahmadi, N., Genestreti, K., Drake, J. F., Liu, Y.-H., Haggerty, C., Eastwood, J. P., Shay, M. A., Pyakurel, P. S., et al.
    Physics of Plasmas (2021) · doi:10.1063/5.0072182
  16. Energy Transfer in Reconnection and Turbulence
    Adhikari, S., Parashar, T. N., Shay, M. A., Matthaeus, W. H., Pyakurel, P. S., Fordin, S., Stawarz, J. E., & Eastwood, J. P.
    Physical Review E (2021) · doi:10.1103/PhysRevE.104.065206
  17. Prevalence of Magnetic Reconnection in the Near-Sun Heliospheric Current Sheet
    Phan, T. D., Lavraud, B., Halekas, J. S., Øieroset, M., Drake, J. F., Eastwood, J. P., Shay, M. A., Pyakurel, P. S., et al.
    Astronomy & Astrophysics (2021) · doi:10.1051/0004-6361/202039863
  18. Parker Solar Probe Observations of Proton Beams Simultaneous with Ion-scale Waves
    Verniero, J. L., Larson, D. E., Livi, R., Rahmati, A., McManus, M. D., Pyakurel, P. S., et al.
    The Astrophysical Journal Supplement Series (2020) · doi:10.3847/1538-4365/ab86af
  19. Reconnection from a Turbulence Perspective
    Adhikari, S., Shay, M. A., Parashar, T. N., Pyakurel, P. S., Matthaeus, W. H., Godzieba, D., Stawarz, J. E., Eastwood, J. P., & Dahlin, J. T.
    Physics of Plasmas (2020) · doi:10.1063/1.5128376
  20. Transition from Ion-coupled to Electron-only Reconnection: Basic Physics and Implications for Plasma Turbulencefirst author
    Pyakurel, P. S., Shay, M. A., Phan, T. D., Matthaeus, W. H., Drake, J. F., TenBarge, J. M., Haggerty, C. C., Klein, K., Cassak, P. A., Parashar, T. N., Swisdak, M., & Chasapis, A.
    Physics of Plasmas (2019) · doi:10.1063/1.5090403
  21. Electron Magnetic Reconnection without Ion Coupling in Earth's Turbulent Magnetosheathhighlight
    Phan, T. D., Eastwood, J. P., Shay, M. A., Drake, J. F., Sonnerup, B. U. Ö., et al., Pyakurel, P. S., et al.
    Nature 557, 202–206 (2018) · doi:10.1038/s41586-018-0091-5
  22. Super-Alfvénic Propagation and Damping of Reconnection Onset Signaturesfirst author
    Pyakurel, P. S., Shay, M. A., Haggerty, C. C., Parashar, T. N., Drake, J. F., Cassak, P. A., & Gary, S. P.
    Journal of Geophysical Research: Space Physics (2018) · doi:10.1002/2017JA024606

In preparation: Pyakurel, P. S., et al., “Statistical properties of electron-only magnetic reconnection observed by MMS in Earth's magnetosheath”

Funding

Grants

awarded 2024 – 2027

Investigation of the magnetic-to-particle energy conversion parameter in magnetic reconnection

Principal Investigator (Co-Is: M. Shay, Univ. of Delaware; C. Haggerty, Univ. of Hawaiʻi)
NASA Heliophysics Guest Investigator, 80NSSC24K0559
$523,046
awarded 2021 – 2024

Investigation of the occurrence and properties of electron-only reconnection in the Earth's turbulent magnetosheath

Principal Investigator
NASA MMS Early Career grant, 80NSSC21K1481
$205,651
awarded 2020 – 2023

Collaborative Research: GEM: Transition from ion-coupled to electron-only reconnection

Senior Personnel (PIs: M. Shay and T. Phan)
NSF GEM
$171,000
(UC Berkeley portion)

Talks

Invited talks and seminars

  • 2026
    PSP Theory Telecon, Johns Hopkins Applied Physics Laboratory
    “The Dependence of Electron-only Magnetic Reconnection on Plasma Beta and Magnetic Shear: Theory and Observations”
  • 2026
    West Virginia University, Department Colloquium
    “Magnetic Reconnection at the Frontier: Linking Simulations and In-Situ Observations”
  • 2026
    West Virginia University, Research Seminar
    “Magnetic Reconnection Across Scales”
  • 2025
    Geospace Environment Modeling (GEM), Des Moines, IA
    “The dependence of electron-only magnetic reconnection on plasma beta and magnetic shear: Evidence from MMS”
  • 2024
    American Geophysical Union, Washington, DC
    “Detection of large guide field electron-only reconnection in a filamentary current sheet”
  • 2024
    Northumbria University, Solar and Space Physics Seminar, Newcastle, UK
    “Electron-only Magnetic Reconnection: Observations and Simulations”
  • 2023
    American Physical Society, Division of Plasma Physics, Denver, CO
    “Electron-only Magnetic Reconnection: Simulations and Observations”
Show 8 earlier invited talks
  • 2023
    MMS Community Workshop, Boulder, CO
    “MMS Observations of electron-only reconnection embedded in the magnetopause ion jets”
  • 2022
    US–Japan Workshop on Magnetic Reconnection, Monterey, CA
    “A faster form of electron magnetic reconnection with a finite length X-line”
  • 2022
    HERMES DRIVE Science Center (NASA), Monthly Seminar
    “Faster form of electron magnetic reconnection with a finite length X-line”
  • 2021
    Imperial College London, Space Physics Seminar
    “A faster form of electron magnetic reconnection with a finite length X-line”
  • 2021
    Dartmouth College, Engineering-Physics Space Plasma Seminar
    “Exploring magnetic reconnection at different length scales: Observations, simulations, and theory”
  • 2020
    University of Colorado Denver, Seminar Series
    “Inherently Three-Dimensional Electron-Only Magnetic Reconnection”
  • 2018
    Southwest Research Institute, San Antonio, TX
    “Electron scale magnetic reconnection in the turbulent magnetosheath: Kinetic PIC simulation study”
  • 2016
    American Geophysical Union, San Francisco, CA
    “Poynting Flux of Kinetic Alfvén Waves Generated During Magnetic Reconnection”

    Contributed presentations

    30 talks and posters at AGU, APS, GEM, SHINE, EGU and MMS meetings since 2010.

    Show the list
    • 2026 · MMS Science Working Team, Daytona Beach, FL
    • 2025 · UC Berkeley SSL Space Physics Seminar
    • 2024 · UC Berkeley SSL Space Physics Seminar
    • 2024 · SHINE, Juneau, AK
    • 2024 · MMS Science Working Team, San Antonio, TX
    • 2024 · MMS Science Telecon
    • 2023 · MMS Science Telecon
    • 2022 · AGU Fall Meeting, Chicago, IL (oral)
    • 2022 · European Geosciences Union
    • 2022 · MMS Community Workshop, Daytona Beach, FL
    • 2021 · MMS Community Workshop, Waterville Valley, NH
    • 2021 · MMS Science Working Team (two talks)
    • 2020 · AGU Fall Meeting
    • 2020 · MMS Science Working Team (two talks)
    • 2020 · GEM Workshop
    • 2019 · SHINE, Boulder, CO
    • 2019 · GEM Workshop, Santa Fe, NM
    • 2018 · AGU Fall Meeting, Washington, DC
    • 2018 · International School/Symposium for Space Simulations, Los Angeles, CA
    • 2018 · SHINE, Cocoa Beach, FL
    • 2018 · GEM Workshop, Santa Fe, NM
    • 2018 · MMS Science Working Team, San Antonio, TX
    • 2017 · AGU Fall Meeting, New Orleans, LA
    • 2017 · University of Delaware Graduate Research Forum
    • 2017 · SHINE, Quebec, Canada
    • 2016 · GEM Workshop, Santa Fe, NM
    • 2016 · APS Meeting, Newark, DE
    • 2015 · AGU Fall Meeting, San Francisco, CA
    • 2015 · GEM Workshop, Snowmass Village, CO
    • 2010 · National Conference on Undergraduate Research, Missoula, MT

    Teaching and mentoring

    Teaching

    Lectures are interactive: a concept, a worked example, then practice on a similar problem right away. Frequent feedback, clear expectations and a predictable course structure.

    • 2024 –Adjunct Faculty, James Madison UniversityCollege Physics I and II (PHYS 140, 150) · Introductory Astronomy (ASTR 120, online)
    • 2012 – 2014Teaching Assistant and Lab Instructor, University of DelawareFundamentals of Physics I · Introduction to Physics I and II

    Mentoring and outreach

    • 2026 –External member, doctoral dissertation committee of Rushikesh PatilDepartment of Physics and Astronomy, West Virginia University: external examiner for the qualifying examination, advising through the dissertation
    • 2026Undergraduate research mentor of Rajiv Nemani, UC Berkeley SSL (URAP)Electron-only reconnection in the turbulent magnetosheath: MMS data analysis with SPEDAS, multi-spacecraft averaging and gradient techniques
    • 2023Outreach with Harrisonburg High School studentsGraduate school in physics and careers in space science, at James Madison University

    Service

    • Proposal reviewReviewer for NASA Heliophysics proposal panels
    • Journal refereePhysical Review Letters, The Astrophysical Journal, Geophysical Research Letters, Journal of Geophysical Research, Physics of Plasmas, Scientific Reports, Reviews of Modern Plasma Physics
    • Session chairAGU 2024 (SM024, 3D magnetosphere during storms) · MMS 10th Community Workshop 2024 (reconnection theory, electron-only reconnection) · APS DPP 2023 (Plasma Astrophysics I)
    • LeadershipMMS Early Career Lead (2022 – 2023) · Co-convener, Kavli IPMU session on particle acceleration (2021) and an MMS SWT splinter (2021) · Student tutorial on reconnection, GEM 2018
    • MembershipsMMS Science Working Team · SHINE · GEM · American Geophysical Union · American Physical Society

    Contact

    Get in touch

    Emailpspyakurel@berkeley.edu
    OfficeSpace Sciences Laboratory
    7 Gauss Way
    Berkeley, CA 94720
    For studentsStart with the Pyakurel Plasma Lab; questions and suggestions about it are welcome by email.