Mystery of massive flare ejection in the universe clarified

Mystery of massive flare ejection in the universe clarified

Dec 20, 2019Engineering

A group of researchers from ELI-Beamlines (Czech Republic), University of Pisa (Italy), and the Institute of Laser Engineering of Osaka University has clarified mechanisms behind the release of high-energy particles and light in the universe.

There are many astronomical objects that emit high-energy particles and light. For example, the Crab Nebula, a supernova remnant, emits high-energy gamma rays. It is thought that its mechanism is related to magnetic reconnection (MR), namely the breaking and reconnecting of oppositely directed magnetic field lines in a plasma, but the mechanisms were not well known.

MR plays a fundamental role in generating auroras and solar flares, but this group clarified the mechanisms of more powerful phenomena in which MR is involved. In plasma, charged particles such as electrons move with the magnetic field, if any. That is, the field-lines are frozen into a plasma (frozen-in magnetic field lines). In a region where MR takes place, magnetic fields annihilate and the magnetic field freezing-in breaks.

However, at extremely high temperatures, electrons become heavy due to relativistic effects, and inter-particle collisions produce a non-adiabatic region in which the magnetic field freezing-in breaks. As electrons are further accelerated, the strength of the inductive electric field reaches about 30 GV voltage/1cm, creating plasma jets of 99 percent the speed of light. The plasma jets are released in the form of high-energy particle beams (gamma rays). The group presented this process using 3-dimensional kinetic simulations.

The results of this study will lead to the clarification of unknown mechanisms of gamma-ray flares from supernova remnants, and gamma-ray bursts, the energy of which is thought to come from the collapse of matter into a black hole.

This group clarified the mechanisms behind the release of high-energy particles and light. Since this phenomenon can be reproduced in the laboratory using strong laser beams, their achievements will lead to the development of new particle generation devices.

Figure 1

The article, “Electromagnetic Burst Generation during Annihilation of Magnetic Field in Relativistic Laser-Plasma Interaction,” was published in Scientific Reports at DOI:

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