Liu, Ningyu

Associate Professor
Physics and Space Sciences

Educational Background

B.S. Zhejiang University 1998

M.S. Zhejiang University 2001

Ph.D. The Pennsylvania State University 2006

Recognition & Awards

NSF CAREER AWARD, 2010

Young Scientist Award, International Union of Radio Science (URSI), 2008

NSF CEDAR Postdoctoral Fellowship, 2006 – 2007

A. J. Ferraro Award for Excellence in PhD Research, Pennsylvania State University, 2005

Outstanding Graduate Student Award, Zhejiang University, 1999
 
Honor of Excellent Graduate of Zhejiang University, Zhejiang University, 1998
 

AWARDS RECEIVED BY ADVISED STUDENTS

  • S. Sadighi, Honorable Mention at 2012 NSF CEDAR Student Poster Competition, 2012
  • B. Kosar, Outstanding Student Paper Award at American Geophysical Union Fall Meeting, 2011
  • B. Kosar, Best Student Poster Prize at NSF CEDAR Workshop, 2011
  • S. Sadighi, NSF Graduate Research Fellowship (Honorable Mention), 2011
  • B. Kosar, Outstanding Graduate Student, Florida Tech, 2010
  • G. Naranjo, Student Design Showcase Award, Florida Tech, 2010
  • B. Kosar, Outstanding Graduate Student, Florida Tech, 2009

Current Courses

Undergraduate Courses: Introductory Physics, Modern Physics, Thermodynamics, and Electromagnetic Theory

Graduate Courses: Electromagnetic Theory 1 and 2

Professional Experience

Associate Professor, Department of Physics and Space Sciences, Florida Institute of Technology, 2012-present

Assistant Professor, Department of Physics and Space Sciences, Florida Institute of Technology, 2008-2012

NSF CEDAR Postdoc, Department of Electrical Engineering, The Pennsylvania State University, 2006-2007

Adjunct Faculty, Penn State DuBois Campus, The Pennsylvania State University, Fall 2006

Research Assistant, Department of Electrical Engineering, The Pennsylvania State University, 2001-2006

Research Assistant, Department of Electrical Engineering, Zhejiang University, 1998-2001

Current Research

SPRITES

Sprites are large air discharges in the mesosphere and lower ionosphere region, which are discovered about twenty years ago and are directly related to lightning activities in underlying thunderstorms. Dr. Liu’s work focuses on building computer models to simulate the development of the internal, filamentary structures of sprites and their associated optical emissions. He also collaborates with experimentalists to validate the model using ground- and satellite-based measurements.

LIGHTNING

Lightning is one of the most spectacular atmospheric phenomena on the Earth. Surprisingly, the initiation and propagation of lightning in thunderclouds is still a mystery. Dr. Liu is currently investigating the possibility of the initiation of lightning from thundercloud hydrometeors.

APPLICATIONS OF LOW-TEMPERATURE PLASMAS

The filamentary structures observed in sprites are the same phenomenon known as streamer discharges at atmospheric pressure. Streamer discharges are one type of low-temperature plasmas. They have been widely utilized in many industrial applications. Dr. Liu is currently examining the applications of streamers in combustion systems and materials processing.

Selected Publications

REFEREED JOURNAL PUBLICATIONS

Kosar, B. C., N. Y. Liu, and H. K. Rassoul, Luminosity and propagation characteristics of sprite streamers initiated from small ionospheric disturbances at sub-breakdown conditions, Journal of Geophysical Research, 117, A08328, doi:10.1029/2012JA017632, 2012. [PDF]

Liu, N. Y., B. Kosar, S. Sadighi, J. R. Dwyer, and H. K. Rassoul, Formation of streamer discharges from an isolated ionization column at sub-breakdown conditions, Physical Review Letters, 109, 025002, 2012. [PDF]

Liu, N. Y., J. R. Dwyer, and H. K. Rassoul, Effects of pressure and humidity on positive corona inception from thundercloud hydrometeors, Journal of Atmospheric and Solar-Terrestrial Physics, 10.1016/j.jastp.2012.01.012, 2012. [PDF]

Liu, N. Y., Multiple ion species fluid modeling of sprite halos and the role of electron detachment of O- in their dynamics, Journal of Geophysical Research, 117, A03308, doi:10.1029/2011JA017062, 2012. [PDF]

Liu, N. Y., V. P. Pasko, H. C. Stenbaek-Nielsen, and M. G. McHarg, Sprite streamers imaged at different exposure times, IEEE Transactions on Plasma Science, 39(11), 2710, 2011. [PDF]

Liu, N. Y., Model of sprite streamer luminous trail caused by increasing streamer current, Geophysical Research Letters, L04102, doi:10.1029/2009GL042214, 2010. [PDF]

Liu, N. Y., and V. P. Pasko, NO-gamma emissions from streamer discharges: Direct electron impact excitation versus resonant energy transfer, Journal of Physics D: Applied Physics, 43, 082001, doi:10.1088/0022-3727/43/8/082001, 2010. [PDF]

Liu, N. Y., V. P. Pasko, K. Adams, H. C. Stenbaek-Nielsen, and M. G. McHarg, Comparison of acceleration, expansion and brightness of sprite streamers obtained from modeling and high-speed video observations, Journal of Geophysical Research, 114, A00E03, doi:10.1029/2008JA013720, 2009. [PDF]

Liu, N. Y., V. P. Pasko, H. Frey, S. Mende, H.-T. Su, A. Chen, R. R. Hsu, and L.-C. Lee, Assessment of sprite initiating electric fields and quenching altitude of a1Πg state of N2 using sprite streamer modeling and ISUAL spectrophotometric measurements, Journal of Geophysical Research, 114, A00E02, doi:10.1029/2008JA013735, 2009. [PDF]

Liu, N. Y., S. Celestin, A. Bourdon, V. P. Pasko, P. Segur, and E. Marode, Photoionization and optical emission effects of positive streamers in air at ground pressure, IEEE Transactions on Plasma Science, 36(4), 942, doi:10.1109/TPS.2008.927088, 2008. [PDF]

Liu, N. Y., S. Celestin, A. Bourdon, V. P. Pasko, P. Segur, and E. Marode, Application of photoionization models based on radiative transfer and the Helmholtz equations to studies of streamers in weak electric fields, Applied Physics Letters, 91, 211501, doi:10.1063/1.2816906, 2007. [PDF]

Liu, N. Y., and V. P. Pasko, Modeling studies of NO-gamma emissions of sprites, Geophysical Research Letters, 34, L16103, doi:10.1029/2007GL030352, 2007. [PDF]

Bourdon, A., V. P. Pasko, N. Y. Liu, S. Celestin, P. Segur, and E. Marode, Efficient models for photoionization produced by non-thermal gas discharges in air based on radiative transfer and Helmholtz equations, Plasma Sources Science and Technology, 16, 656-678, doi:10.1088/0963-0252/16/3/026, 2007. [PDF]

Liu, N. Y., and V. P. Pasko, Effects of photoionization on similarity properties of streamers at various pressures in air, Journal of Physics D: Applied Physics, 39, 327-334, doi:10.1088/0022-3727/39/2/013, 2006. [PDF]

Moss, G. D., V. P. Pasko, N. Y. Liu, and G. Veronis, Monte Carlo model for analysis of thermal runaway electrons in streamer tips in transient luminous events and streamer zones of lightning leaders, Journal of Geophysical Research, 111, A02307, doi:10.1029/2005JA011350, 2006. [PDF]

Liu, N. Y., V. P. Pasko, D. H. Burkhardt, H. Frey, S. Mende, H.-T. Su, A. Chen, R. R. Hsu, L.-C. Lee, H. Fukunishi, and Y. Takahashi, Comparison of results from sprite streamer modeling with spectrophotometric measurements by ISUAL instrument on FORMOSAT-2 satellite, Geophysical Research Letters, 33, L01101, doi:10.1029/2005GL024243, 2006. [PDF]

Liu, N. Y., and V. P. Pasko, Molecular nitrogen LBH band system far-UV emissions of sprite streamers, Geophysical Research Letters, 32, L05104, doi:10.1029/2004GL022001, 2005. [PDF]

Liu, N. Y., and V. P. Pasko, Effects of photoionization on propagation and branching of positive and negative streamers in sprites, Journal of Geophysical Research, 109, A04301, doi:10.1029/2003JA010064, 2004. [PDF]

PH.D. THESIS

Liu, N. Y., Dynamics of Positive and Negative Streamers in Sprites, Ph.D. thesis, The Pennsylvania State University, University Park, Pennsylvania, 2006. [PDF]