Lunjin Chen

Assistant Professor - Physics
lunjin.chen@utdallas.edu
972-883-2891
WTC2706
Tags: Physics

Professional Preparation

Ph.D. - Space Physics
University of California, Los Angeles - 2011
M.S. - Space Physics
University of Science and Technology of China - 2007
B.S. - Geophysics
University of Science and Technology of China - 2004

Research Areas

Research Interests
  • Magnetospheric physics
  • Interaction of electromagnetic waves and energetic charge particles in geospace plasma
  • Modeling of radiation belt dynamics
  • Instability and propagation of plasma waves
  • Applications of plasma waves
Research Description

The Earth’s magnetosphere, our geospace environment a few thousand kilometers above the Earth’s surface, consists of energetic charge particles trapped by the Earth’s magnetic field. Those energetic particles exhibit great variability due to solar activities, and pose a great threat to spacecraft orbiting in it and to astronauts. Understanding and predicting their variability are of great interest for space weather. A variety of naturally occurring electromagnetic waves, from Ultra Low Frequency to Very Low Frequency, play important roles in dynamics of those energetic charge particles, especially the radiation belts referring to population of electrons and protons with relativistic energy in geospace. The physical process involved is called wave-particle resonant interaction, where electromagnetic waves seen by particles match fundamental frequencies of trapped particles, leading to stochastic change in particles’ energy and momentum. My research interest is to study the nature of electromagnetic waves in our geospace and the effect of wave-particle interaction. We use various numerical simulation techniques to address the following questions, how are electromagnetic waves generated due to what kind of free energy, how do them propagate in complex geospace medium, where is the wave energy absorbed, how those waves affect energetic particles, and how do we model temporal evolution and spatial distribution of energetic particle population due to wave-particle interaction. These questions are the compelling science topics of the NASA’s $700M two-twin Van Allen Probes Mission. The mission, named after Dr. Van Allen who made the discovery of the radiation belts in 1958, was launched in 2012 August and aims at identifying fundamental mechanisms responsible for radiation belt loss and acceleration.

 

For more information on Van Allen Probes from NASA

http://www.nasa.gov/mission_pages/rbsp/main/#.UmgnQJRgZcs

or from youtube (search for “Van Allen probes”)

http://www.youtube.com/watch?v=fkUc7dTfGoA

or from wiki

http://en.wikipedia.org/wiki/Van_Allen_radiation_belt

Publications

Chen, L., R. Thorne, Y. Shprits, and B. Ni,  An improved dispersion relation for parallel propagating electromagnetic waves in warm plasmas: Application to electron scattering, J. Geophys. Res., 118, doi:10.1029/2012JA018371. 2013 - Publication
Chen, L., R. Thorne, W. Li, and J. Bortnik, Modeling the Wave Normal Distribution of Chorus Waves, J. Geophys. Res., 118, doi:10.1029/2012JA018343. 2013 - Publication
Omidi, N., J. Bortnik, R. Thorne, and L. Chen, Impact of cold O+ ions on the generation and evolution of EMIC waves, J. Geophys. Res., 118, 434-445, doi:10.1029/2012JA018319. 2013 - Publication
Meredith, N. P., R. B. Horne, J. Bortnik, R. M. Thorne, L. Chen, W. Li, and A. Sicard-Piet, Global statistical evidence for chorus as the embryonic source of plasmaspheric hiss, Geophys. Res. Lett., 40, doi:10.1002/grl.50593. 2013 - Publication
Li, W., J. Bortnik, R. Thorne, C. Cully, L. Chen, V. Angelopoulos, T. Nishimura, J. Tao, J. Bonnell, and O. LeContel, Characteristics of the Poynting flux and wave normal vectors of whistler-mode waves observed on THEMIS, J. Geophys. Res., 118, 1461–1471, doi:10.1029/2012JA018609. 2013 - Publication
de Soria-Santacruz, M., M. Spasojevic, and L. Chen, EMIC waves growth and guiding in the presence of cold plasma density irregularities, Geophys. Res. Lett., 40, doi:10.1002/grl.50484. 2013 - Publication
Vania Jordanova, Daniel Welling, Sorin Zaharia, Lunjin Chen, and Richard Thorne (2012), Modeling ring current ion and electron dynamics and plasma instabilities during a high-speed stream driven storm, 117, A00L08, J. Geophys. Res., doi:10.1029/2011JA017433 2012 - Publication
Lunjin Chen, Jacob Bortnik, Wen Li, Richard Thorne, and Richard Horne (2012), Modeling the Properties of Plasmaspheric Hiss: 1. Dependence on Chorus Wave Emission, J. Geophys. Res., 117, A05201, doi:10.1029/2011JA017201 2012 - Publication
Justin Lee, Lunjin Chen, Vassilis Angelopoulos, and Richard Thorne (2012), THEMIS observations and modeling of multiple ion species and EMIC waves: implications for a vanishing He+ stop band, 117, A06204, J. Geophys. Res., doi:10.1029/2012JA017539. 2012 - Publication
Lunjin Chen, Jacob Bortnik, Wen Li, Richard Thorne, and Richard Horne (2012), Modeling the Properties of Plasmaspheric Hiss: 2. Dependence on the Plasma Density Distribution, J. Geophys. Res., 117, A05202, doi:10.1029/2011JA017202 2012 - Publication

Appointments

Assistant Researcher
UCLA [2013–2013]
Assistant Professor
UT, Dallas [2013–Present]
Postdoctoral Researcher
UCLA [2011–2013]
Graduate Student Researcher
UCLA [2007–2011]

Awards

Young Investigator Award - USAF [2016]

Additional Information

Awards and Honors
  • 2012 American Geophysical Union Space Physics and Aeronomy Section‘s 2012 Fred L. Scarf Award
    Given annually to a recent recipient of a Ph.D. for outstanding dissertation researchthat contributes directly to solar-planetary science.
  • 2012 Nominee for the Chancellor‘s Award for Postdoctoral Research, UCLA.
    The award is given to recognize the important contributions that postdoctoral scholars from a variety of academic areas make to UCLA’s research mission.
  • 2010 Jacob A. Bjerknes Award.
    Given for graduate students of the outstanding research by the Department of Atmospheric and Oceanic Sciences, UCLA

News Articles

Scientist's Space Weather Work Gets Support from Air Force Grant
Beyond Earth’s breathable atmosphere, above the strata where airplanes fly and meteoroids burn up into shooting stars, lies a dynamic region between our planet and the sun, and what happens there is intricately connected to our everyday lives. 
Dr. Lunjin Chen
, an assistant professor of physics at UT Dallas, recently received a three-year, approximately $360,000 grant through the Air Force’s Young Investigator Research Program to study “space weather” in this region, called the magnetosphere.