Laboratory and astrophysical plasmas

Professor Tony Bell

Senior Research Fellow

Joint appointment at the Central Laser Facility, Rutherford Appleton Laboratory

Visiting Professor at Imperial College

Clarendon Laboratory Room 122.2
Phone: +44 (0) 1865 272210
Fax: +44 (0) 1865 272375
Email: t.bell1@physics.ox.ac.uk

Theoretical plasma physics

Plasma is the state of matter, usually very hot, in which atoms separate into positively charged ions and negatively charged electrons which interact through long range electric and magnetic fields.  Plasmas occur in widely differing circumstances with many applications, varying from fusion plasmas aimed at thermonuclear generation of clean energy to astrophysical plasmas which constitute most of the visible matter in the universe.  Our interests are centred on the theory of high energy phenomena in astrophysics and in plasmas produced by high power lasers.  The connecting factor is that the physics of energetic (MeV) electrons generated by high power lasers is similar to that of cosmic rays with energies up to 10²⁰eV.  In both cases, the energetic particles are responsible for the generation of magnetic field which in turn determines the particle trajectories and their acceleration.  We apply the same mathematical and computer simulation techniques to laboratory experiments and astronomical observations.  We are looking at ways in which energetic electrons might be used to ignite fusion pellets to generate clean thermonuclear energy. The next generation of high power lasers should be able to produce electron-positron pair plasmas with relevance to pulsar and black hole magnetospheres.

Key Publications

Resistive magnetic field generation at cosmic dawn Miniati F & Bell AR , arXiv:1001.2011 (2010)

Possibility of prolific pair production with High-Power Lasers Bell AR & Kirk JG, Physical Review Letters 101, 200403 (2008)

Turbulent amplification of magnetic field and diffusive shock acceleration of cosmic rays Bell AR, Monthly notices of the royal astronomical society, 353, 550 (2004)

Resistive collimation of electron beams in laser-produced plasmas Bell AR; Kingham RJ, Physical review letters, 91,035003 (2003)

Electron energy-transport in steep temperature-gradients in laser-produced plasmas Bell AR, Evans RG & Nicholas DJ, Physical review letters, 46, 243 (1981)

The acceleration of cosmic rays at shock fronts Bell, AR, Monthly notices of the royal astronomical society, 182, 147 (1978)