Space Physics and Energetic Particles Research


Our group studies energetic particles from space, known as cosmic rays, including analytic theory, computer simulations, and an observing station.  Our particular interest concerns solar storms, sudden explosions at the surface of the Sun, and their effects on Earth, known as space weather.  Space weather effects include radiation hazards to astronauts due to cosmic rays; satellite or spacecraft failures; disturbances to the ionosphere, radio communications, and GPS positioning; and sudden, destructive currents in power stations, pipelines, and undersea cables on Earth.  Our group provided the first theoretical explanation of how solar effects on galactic cosmic rays can help in forecasting the onset of space weather effects at Earth.

      We are coordinating the installation of the Princess Sirindhorn Neutron Monitor station, named in honor of HRH Princess Sirindhorn, at Thailand’s highest mountain, Doi Inthanon in Chiang Mai Province, to monitor the flux of galactic cosmic rays from space.  The monitor is being established in collaboration with Chulalongkorn University and Ubonrajathanee University in Thailand, Shinshu University in Japan, and the University of Delaware in the US.  This monitor will make a substantial contribution to the worldwide neutron monitor network, especially because it will have the world’s highest cutoff rigidity (i.e., our neutron monitor will measure the particles of highest energy).  We particularly welcome new students or researchers to join our group or collaboration to make use of the new data from this upcoming cosmic ray detector.

      Another line of work is to use analytic theory and computer simulations to develop new concepts regarding the random walk of magnetic field lines and energetic particles in space.  The particles mostly circle around field lines, so the field lines guide particles from a source to the observer.  However, most space plasmas have turbulent flows, so the magnetic field is highly irregular.  We have identified topological features of two-dimensional turbulence that can serve to temporarily trap magnetic field lines and provide small flux tubes (with sharp boundaries) with direct magnetic connection from the particle source (e.g., a solar flare) to the observer.

      Finally, our group is most recognized internationally for our leading work on precision modeling of the transport of solar energetic particles, due to solar storms, from the Sun to the Earth.  With precise computational solutions to a partial differential equation for particle transport (developed in Thailand), we can infer precise timing of particle acceleration near the Sun; the magnetic field configuration in space; and interplanetary transport conditions.   With our unique expertise, we continue to analyze data from ground-based and space-based detectors at the invitation of foreign collaborators. 

Research activities

  • Establishing the Princess Sirindhorn Neutron Monitor to observe cosmic rays at Doi Inthanon.
  • Theory and computer simulations of the turbulent random walk of magnetic field lines in space plasmas, including the discovery of temporary trapping in topological features of the turbulence.
  • Precision modeling of observational data from abroad, in order to determine accurate profiles of particle injection near the Sun, the configuration of the interplanetary magnetic field, and particle transport conditions in space.