Chen Shi

Assistant Researcher
Department of Earth, Planetary, and Space Sciences
University of California, Los Angeles

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About Me

My Selfie

I am now an assistant researcher at Department of Earth, Planetary, and Space Sciences, UCLA.

I work with Professor Marco Velli and my research focuses on solar physics, especially topics on solar wind turbulence, magnetic reconnection, and origin of the solar wind.

Here is my CV, and my Google Scholar page.

Projects

Solar Wind

Origin of the solar wind

Solar wind is the hot and supersonic plasma flow that is ejected from the solar atmosphere. It carries a significant amount of energy and causes various space weather events, e.g. magnetic storms, when it hits the Earth's magnetetoshphere.

Where does the solar wind originate and how does it gain sufficient energy to escape the solar gravity and reach a supersonic speed are still far from being completely understood. I have been working on theories and modeling of the solar wind generation, including development of polytropic solar wind model, and conducting simulations of Alfvén wave driven solar wind.

Turbulence

Solar wind turbulence

Turbulence is ubiquitos in the solar wind. It refers to the fluctuations that span across a huge range of spatial and temporal scales. It is believed to be a major energy source for the heating and acceleration of the solar wind.

My work focuses on the evolution of solar wind turbulence at MHD scales. By combining satellite observations and numerical simulations, I analyze how the large-scale structures, including stream-interaction-regions (SIRs) and heliospheric current sheet (HCS), affect the turbulence properties. Using Parker Solar Probe measurements, I study the early-stage evolution of the turbulence and how the turbulence properties depend on the source of the solar wind.

Magnetic reconnection

Magnetic reconnection

Magnetic reconnection is a fundamental process in plasma. It happens between anti-parallel magnetic field lines and converts the magnetic energy into the kinetic and internal energy of the plasma. It is believed to be an important energy source for the coronal heating and solar wind acceleration, and it is the key process underlying different space weather phenomena.

To understand how reconnection happens explosively at MHD scales, I have carried out theoretical and numerical studies of the stability problem of plasma current sheets. I analyze the growth of linear tearing mode instability in the current sheets with different configurations and conduct numerical simulations of the nonlinear evolution of the current sheets that are susceptible to the tearing mode instability.

3D MHD simulation

High performance computing

With the rapid advancement of computing capability, large-scale numerical simulations become more and more important in the research of space physics and plasma physics.

I have been developing 3D (Hall-)MHD simulation codes that are parallelized with Message-Passing-Interface (MPI). The codes adopt Fourier transform based pseudo-spectral method and compact-finite-difference method to evaluate spatial derivatives, and explicit Runge-Kutta method for time advancement. Our codes are especially suitable for simulations of turbulence and recursive magnetic reconnection that require precise resolution of small-scale structures.

Selected publications

For a complete publication list, please refer to my CV

  1. Analytic model and MHD simulations of three-dimensional magnetic switchbacks, Chen Shi, Marco Velli, Gabor Toth, et al., 2023, arXiv:2401.11334
  2. Evolution of MHD turbulence in the expanding solar wind: residual energy and intermittency, Chen Shi, Nikos Sioulas, Zesen Huang, et al., 2023, arXiv:2308.12376
  3. Proton and electron temperatures in the solar wind and their correlations with the solar wind speed, Chen Shi, Marco Velli, Roberto Lionello, et al., 2023, ApJ, 944, 82
  4. Acceleration of polytropic solar wind: Parker Solar Probe observation and one-dimensional model, Chen Shi, Marco Velli, Stuart Bale, et al., 2022, PoP, 29, 12
  5. Patches of Magnetic Switchbacks and Their Origins, Chen Shi, Olga Panasenco, Marco Velli, et al., 2022, ApJ, 934, 152
  6. Instabilities in a current sheet with plasma jet, Chen Shi, 2022, JPP, 88, 4
  7. Influence of the heliospheric current sheet on the evolution of solar wind turbulence, Chen Shi, Marco Velli, Anna Tenerani, et al., 2022, ApJ, 928, 93
  8. Stability of the magnetotail current sheet with normal magnetic field and field-aligned plasma flows, Chen Shi, Anton Artemyev, Marco Velli, et al., 2021, JGR Space Physics, 126, 11
  9. Alfvénic versus non-Alfvénic turbulence in the inner heliosphere as observed by Parker Solar Probe, Chen Shi, Marco Velli, Olga Panasenco, et al., 2021, A&A, A21, 12
  10. Oblique Tearing Mode Instability: Guide Field and Hall Effect, Chen Shi, Marco Velli, Fulvia Pucci, Anna Tenerani & Maria Elena Innocenti, 2020, ApJ, 902, 2
  11. Propagation of Alfvén waves in the expanding solar wind with the fast-slow stream interaction, Chen Shi, Marco Velli, Anna Tenerani, Franco Rappazzo & Victor Réville, 2020, ApJ, 888, 2
  12. Fast Recursive Reconnection and the Hall Effect: Hall-MHD Simulations, Chen Shi, Anna Tenerani, Marco Velli & San Lu, 2019, ApJ, 883, 172
  13. Marginal Stability of Sweet-Parker Type Current Sheets at Low Lundquist Numbers, Chen Shi, Marco Velli & Anna Tenerani, 2018, ApJ, 859, 83

Contact Me

Email: Chen Shi.

Address: Slichter Hall 6844-C, 603 Charles E Young Dr E, Los Angeles, CA 90095.