add gas/grain drift in grain collisional physics (trac #85)

[cloudy-bot]

reported by: peter

The gas/grain drift will alter the average relative velocity between grains and incoming ions / atoms / molecules. This will alter both the collision rate and the energy of the incoming particle. We know the drift velocity, so we should be able to account for this effect in the grain collisional physics.

Migrated from https://www.nublado.org/ticket/85

{
    "status": "new",
    "changetime": "2019-02-04T13:07:06Z",
    "_ts": "1549285626580696",
    "description": "The gas/grain drift will alter the average relative velocity between grains and incoming ions / atoms / molecules. This will alter both the collision rate and the energy of the incoming particle. We know the drift velocity, so we should be able to account for this effect in the grain collisional physics.",
    "reporter": "peter",
    "cc": "",
    "resolution": "",
    "time": "2009-03-04T17:23:56Z",
    "component": "grains",
    "summary": "add gas/grain drift in grain collisional physics",
    "priority": "minor",
    "keywords": "",
    "version": "",
    "milestone": "no milestone",
    "owner": "peter",
    "type": "physics"
}

[cloudy-bot]

@peter-van-hoof-noaccount changed milestone from "" to "no milestone"