tusenfem
Illuminator
- Joined
- May 27, 2008
- Messages
- 3,306
Are you able to expand on some of the points raised in this short presentation? Namely negatively charged dust grains and the sputtering of the comets surface by the solar wind, in relation to the paper by Andrew Coates and how this may effect cometary jets?
Dust lifted off the comet, into the mixed solar wind and comet-produced plasma, tends to become negatively charged, because electrons colliding with the dust often stick to the dust. This is a well known phenomenon of dusty plasmas. (if the grains get bigger, though, the dust can also be positively charged, making things even more complicated).
High-energy particles impacting on any solar system surface produce "sputtering" in which the particle hits the surface and breaks off molecules off the surface (at Europa for example water, sulphur, chlorine etc.). These molecules are mostly neutral, but get ionized by UV radiation of the Sun and then picked-up by the solar wind magnetic field.
Dust charge and sputtering have, IMHO, little to do with cometary jets. There is no discussion of jets in Andrew's paper, nor in the presentation. The only thing is that jets deposit more dust from the surface of the comet.


