Montag, 13. Februar 2012 - 11:00
Satoshi Okuzumi(Nagoya Univ.):
"Introduction to grain charging in a plasma environment"
Zusammenfassung. Collisional growth of dust grains is the first step of planet formation. However, several effects have been pointed out so far that can prevent grain growth in protoplanetary disks. In this talk, I will focus on one of them, the so-called "charge barrier", and will explain the essence of it as simply as possible. I will show, with a simple order-of-magnitude estimate, that 1) dust grains in a neutral plasma carry negative net charges, and 2) the charging prevents (thermally moving) grains from growing beyond micrometer sizes. I will also explain important differences between a simple neutral plasma environment and a more complex protoplanetary disk environment. This will be useful to understand the charge barrier in real astrophysical systems.