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Particle acceleration in MHD turbulence

Event Details

Event Dates: 

Friday, April 22, 2016 - 12:00pm

Seminar Location: 

  • JILA 10th Floor - Foothills Room

Speaker Name(s): 

Andrey Beresnyak

Speaker Affiliation(s): 

NRL Washington
Seminar Type/Subject

Scientific Seminar Type: 

  • Astrophysics Lunch Seminar

Event Details & Abstract: 

MHD Turbulence describes dynamics of astrophysical plasmas on large scale. It is characterized by energy transfer between different scales and the exchange of energy with nonthermal population -- typically cosmic rays. Recent progress in theory regarding almost all basic regimes of turbulence -- from the dynamo to the decaying case and the asymptotic scaling laws, allowed us to proceed with more observationally motivated questions. One of them is why almost all strongly magnetized environments are indeed observable, e.g. why such environments are infused with high-energy particles, their distributions stretching to energies orders of magnitude higher than thermal. It turns out that there are generic mechanisms of acceleration in turbulence, both second and first order in v/c, the latter was somehow unnoticed. These generic mechanisms may explain the ubiquity of non-thermal tails in various magnetized astrophysical environments, e.g. solar chromosphere, pulsar magnetospheres, jets from supermassive black holes, gamma-ray bursts, etc.