V: Comparing Plasma & Vacuum - ICP Instrument

[haiha]

I used to work with a ICP instrument for a while. There's a phenomenon which I tried to explain but it seems not clear enough.
In the instrument, just imagine there are a vacuum chamber and a plasma torch. The vacuum chamber has an inlet with a diameter of about 1mm. If the plasma is off, the inlet is shut. Only when the plasma is on, the inlet is open and the vacuum can hold, otherwise, there's no vacuum. This vacuum is not so high, it's the intermediate stage.
I always thought plasma is high pressure, high temp, so it shoud elimilate the vacuum, but it does the opposite!.
Thanks for reading the thread.

HH

 

[russ_watters]

Plasma is high temperature, not necessarily high pressure.

 

[haiha]

You are right, plasma may not be high pressure, but how can I explain that plasma can seal the vacuum hole?