Cosmic Rays in super Bubbles

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A century-long standing problem in astrophysics is to explain how cosmic rays are accelerated to relativistic energies and how they diffuse in their host galaxy. Notable progress has been made on their production in supernova remnants, but the recent discovery in gamma rays, with the Fermi satellite, of a cocoon of fresh and energetic cosmic rays in the Cygnus X superbubble has disclosed an important new facet of the problem : what is the impact on particle (re-)acceleration and diff usion of the large level of turbulence generated in the superbubble medium by the activity of the numerous massive stars ? Can this turbulent phase signi cantly modify our current views on cosmic-ray transport in the Galaxy because most cosmic-ray sources are to be found in active star-forming regions ? In this project, we propose to compare two superbubbles, the few-million-year old, bursting Cygnus X bubble and the older, less energetic Orion-Eridanus superbubble near the Sun. We propose to combine our expertise on cosmic-ray transport/acceleration, on gamma -ray observations of cosmic rays, and on multi-wavelength observations of the interstellar conditions prevailing in these bubbles, in order to test a new acceleration mechanism and to revisit the impact of the turbulent bubble medium on diff erent observational cosmic-ray diagnostics, Galactic-wide and locally in the Local Superbubble.