40-S2-D01 - Salle Dirac
The possible influence of cosmic rays on aerosols and clouds is of considerable interest. The CLOUD (Cosmic leaving outdoor droplets) experiment at CERN aims to study under controlled conditions the effects of cosmic rays on particle formation, cloud droplets and ice particles. In the atmosphere, some molecules can agglomerate to form a “big” particle which can act as a seed for a cloud droplet. The number and size of droplets affect the clouds’ properties like their brightness or life time, and therefore influence the climate. Using the CLOUD chamber, different mechanisms of particle formation are investigated under various controlled atmospheric conditions, like temperature, humidity, air purity and ionization. The CERN Proton Synchrotron beam is used to vary the ionization rate of the molecules inside the CLOUD chamber, like natural galactic cosmic rays do in the atmosphere. This allows to quantify the effect of the variation of galactic cosmic rays on cloud seed formation.
Organizer: Joachim Baechler PH-TOT