Atmospheric Electricity and Hard Radiation from Thunderclouds

Research School at the Birkeland Centre for Space Science

 

When:                 May 20-24, 2019
Where:                Dept. of Physics and Technology, University of Bergen, Allégaten 55, Bergen, Norway

For Whom:         Master’s, PhD students and early career scientists

School hours:

  • 30 lectures, 45 minutes/lecture
  • Total: 334 pages reading
    • 144 pages of descriptive information
    • 80 pages theory
    • 110 pages from scientific journal articles

Project:               Estimated 4 weeks of work – submitted to and evaluated at UiB
ETCS credits:    10 (given by UiB; credits must be approved by the home university)
Registration:      Deadline February 1, 2019

Financial support:
    For students who do not have their own support, limited financial aid is available for travel expenses and accommodation. Applications, including a support letter from a supervisor, should be submitted before February 1, 2019.

Application:       Click here

Description:

The research school on Atmospheric Electricity and Hard radiation from Thunderclouds will give the student an understanding of the basic mechanisms and physics involved in the production and electrification of thunderclouds. The students will also become familiar with observations of different types of lightning by electric field measurements, visible signals and radio-waves. This part of the curriculum will not be taught in class.

A more detailed description and theories for how streamers and leaders are formed and propagate will be given as lectures. This is how electric discharges initiate and how they branch through the air, both as it is observed in nature as lightning and as long sparks in the laboratory

Finally, the main theories for how hard radiation is produced in thunderclouds will be given as lectures. This part will focus on electron relativistic run-away and relativistic run-away electron avalanches in the air and what electric field strengths are needed for these processes to occur. Also, where such fields can be produced in a thundercloud in order to produce tens of MeV electrons and gamma-rays will be studied. Characteristic time-scales, energy spectrum of electrons and terrestrial gamma-rays as they propagate out of the atmosphere will also be derived.

Classes will also include observations of TGFs, discussion of instruments for the detection of TGFs, propagation of photons through the atmosphere, what an Energy Response Matrix is, radio waves from lightning, and long sparks in the laboratory.

Finally, the course will include a project to be completed after the conclusion of the school and submitted for evaluation.


Curriculum:

Background material (self-study, short presentations may be given by the students themselves)
Vladimir A. Rakov and Martin A. Uman (2003) Lightning, Physics and Effects

  • Chapter 1: Introduction (12 pages)
  • Chapter 3: Electrical structure of lightning-producing clouds (27 pages)
  • Chapter 4: Downward negative lightning discharges to ground (84 pages)
  • Chapter 9: Cloud discharges (21 pages)

Theory of lightning and its initiation
Vernon Cooray, The Lightning Flash (2003), (lecture by V. Cooray)

  • Chapter 3: Mechanism of electrical discharges (80 pages)

The production of Terrestrial Gamma-ray Flashes (lecture by J. Dwyer)

  • J.R. Dwyer and M.A. Uman (30 January 2014), The Physics of Lightning, Physics Reports (Vol. 534, Issue 4, Chapter 5), (38 pages)
  • J.R., Dwyer, D. Smith and S.A. Cummer (2012) High Energy Atmospheric Physics: Terrestrial Gamma-ray Flashes and Related Phenomena, Space Science Rev., doi: 10.1007/s11214-012-9894-0 (58 pages)
  • Celestin, S., and V. P. Pasko (2011) Energy and fluxes of thermal runaway electrons produced by exponential growth of streamers during the stepping of lightning leaders and in transient luminous events, J. Geophys. Res., 116 (A3), 1–14, doi:10.1029/2010JA016260 (14 pages)


Project:

Determine the distribution of TGFs detected by AGILE, RHESSI and Fermi in

  • Longitude
  • Latitude
  • Duration
  • Local times
  • Ocean, coast and land

Discuss how and why they are different – different instruments, different orbits etc. Lists of TGFs from the three platforms will be given.