The transport of cosmic rays in the Galaxy: constraints on the diffusion coefficient from gamma ray observations of the W28 region
Invited Talk, TBD
Particules énergétiques piégées autour des planètes magnétisées
A. Sicard-Piet, S. Bourdarie
The magnetic field in the vicinity of the Earth becomes such that all relativistic charged particles are trapped and their movement is then quasi-periodic. These special conditions are thus favorable to the accumulation of high-energy charged particles in certain regions of space which creates the radiation belts. Such radiation belts exist around any magnetized planet. Several way exist to measure particles of the radiation belt, like in-situ data or synchrotron emission in the case of giant planet like Jupiter.
The Sun as a Particle Accelerator:
Hard X-ray, gamma-ray, radio and in-situ diagnostics of energetic particles
Nicole Vilmer LESIA-Paris Observatory
(LESIA-Observatoire de Paris)
Violent phenomena in the solar atmosphere lead to the production of energetic particles and of bubbles of ionized matter which propagate in the interplanetary medium with speeds of several thousands of kilometres per second. The source of the fast particles and of the mass ejections is well known to be linked to the existence of a complex magnetic field at the surface of the Sun. Solar flares are characterized by a fast brightening in the active regions surrounding sunspots and also by intense (several order of magnitudes) enhancements of radio and UV/X-ray emissions from the Sun. During flares, the Sun behaves as an efficient particle accelerator. While some high energy particles (electrons and ions) produce high energy radiation in the solar atmosphere (X-rays and gamma-rays), others will escape in the interplanetary medium, propagate along interplanetary magnetic field lines and eventually reach the Earth's orbit. I shall review here some results (both observational and theoretical) on solar particle acceleration provided by X-ray/ -ray observations obtained by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) mission (as well as by INTEGRAL/SPI). I shall also present some results obtained on electron acceleration and transport in flares provided by the combination of decimetric to kilometric radio observations (from ground-based and space instrumentation) with X-ray spectrally and spatially resolved observations. I shall finally discuss some of the scientific objectives of Solar Orbiter related to the issue of particle acceleration and transport at the Sun and in the inner heliosphere.
Fermi acceleration in astrophysical shock waves
Recent developments in the physics of Fermi acceleration in astrophysical shocks will be reviewed. Special attention will be addressed to supernova shock waves were the cosmic ray streaming instability is expected to produce a highly turbulent magnetic field. Consequences on the origin of the high energy cosmic ray spectrum will be discussed in conclusion.