Energetic charged particles exist ubiquitously around the Universe. Fermi-type mechanisms are believed to be the source. Nevertheless, they need high-energy particles as seeds and this “injection problem” is still an open question. Stochastic acceleration in a turbulent plasma has been proposed as one of the mechanisms to pre-accelerate the seed particles. However, no direct evidence has been found in the laboratory.

Here we report the first observation of stochastic acceleration in a turbulent plasma in the laboratory using high-power lasers coupled with strong magnetic field. Non-thermal protons are experimentally measured, and their energy spectrum hints a stochastic origin, as it can be well-fitted by a Weibull distribution, which is expected from a stochastic process.

Using three-dimensional magneto-hydrodynamic simulations with test particles, we find this stochastic acceleration process is indeed closely associated with the turbulent plasma originated from the magnetic Rayleigh-Taylor instability, which is induced during the dense plasma expanding across the magnetic field. Also, our simulation can qualitatively reproduce the experimental particle spectrum. Such efforts for astrophysically-relevant particle acceleration in the laboratory will certainly provide an alternative for the injection of particles from the thermal background into the Fermi-type mechanisms.

The Large Magellanic Cloud (LMC) is an irregular satellite galaxy of the Milky Way, located in the southern sky at a distance of about 50 kpc. The High Energy Stereoscopic System (H.E.S.S.) is a system of five Imaging Air Cherenkov Telescopes designed to observe the gamma-ray sky at photon energies of more than several hundreds of GeV. H.E.S.S. is so far the only instrument to observe the LMC in this energy range.

H.E.S.S. is observing the LMC since 2004. The scientific goal of these observations was initially to probe of the the onset of particle acceleration in the remnant of the SN 1987A supernova explosion. This object has not been detected in gamma rays. However, these observations lead to the discovery of gamma-ray radiation of several other objects in the LMC. These objects are one of each of the different source classes: pulsar wind nebulae, supernova remnants, superbubbles, gamma-ray binaries and star clusters. It is the first time that individual objects are detected in gamma rays in an external galaxy. It turned out that these sources outshine their counter parts in the Milky Way.

In this talk I will give an overview of the gamma-ray observations of the LMC with H.E.S.S. and I will present the individual gamma-ray sources and the scientific implications of these discoveries. I will show the current status of the ongoing survey of the LMC and discuss open questions that H.E.S.S. may answer after completion of the survey. I will conclude with an outlook on what will be done with the Cherenkov Telescope Array in the future.

Climate change and environmental issues present unprecedented challenges to human societies. Numerous initiatives are emerging in various sectors of society to reduce greenhouse gas emissions and, more broadly, environmental impacts. This is particularly evident in the field of higher education and research. In France, labos1p5 plays a significant role in facilitating the transformation of laboratories, but many challenges persist.

At the laboratory level, a crucial step in the process is the transition from conceptualizing ideas to implementing concrete measures related to collective functioning and professional practices. The purpose of the seminar is to discuss this stage of moving from thought to action, focusing on the conditions for success and pitfalls to avoid. An overview of the LOCEAN's experience, as a laboratory committed to its transformation since 2018, will serve as an introduction to the discussion.