Plasma Current

Discussion in 'Physics' started by Sparky49, Jul 3, 2014.

  1. Sparky49

    Thread Starter Active Member

    Jul 16, 2011
    834
    417
    Hi all.

    I am currently trying to determine the specifications of equipment I need to create a plasma. I am looking to generate a plasma in chamber of Helium at a pressure of about 0.6 Torr. My electrodes are around 17cm apart (giving me a pd of 10 Torr cm). By consulting Paschen curves, I see I need a power supply capable of producing a voltage of 200V. I intend to use continuous DC - not pulsed DC.

    However, I cannot seem to be able to find a means of calculating the current which needs to be delivered. Can anyone suggest a means of finding this out?

    Thank you in advance for your time.

    Best regards,

    Sparky
     
  2. BR-549

    Well-Known Member

    Sep 22, 2013
    2,004
    394
    I don't know the answer to your question, but I don't think it would be a lot of current. And with the nature of ionization, I would think the current would be jumpy. I don't know your intent with the plasma, but have you ever heard of a fusor? These little devices are quite spectacular......but can be dangerous. Keep your voltage down. But you can have nuclear fusion to a small extent, right on your desk. When you get it adjusted just right......you can get a "star" effect. Google and youtube "fusor". If you build something....let us know how it turns out.
     
  3. BR-549

    Well-Known Member

    Sep 22, 2013
    2,004
    394
    Also...I know nothing about this but.......even at that pressure,......with that wide of a gap.........isn't 200 volts a little skimpy?
     
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,795
    951
    for a sustanded arc the amperage could become un-realistic for home/hobby type arrangements. All references I find are to pulsed currents. These come from capacitor banks etc. perhaps SLA batteries could supply enough current to prevent voltage sag, but you would need many of them to reach your target voltage
     
  5. #12

    Expert

    Nov 30, 2010
    16,340
    6,824
    Think about your spark gap like a fluorescent tube. Use an inductor in series. The inductor will limit the current (Xl=2PiFL) and provide enough voltage to re-strike the arc every half cycle.

    Look to a High Pressure Sodium light fixture for the "ignitor" required for the start-up.
     
  6. BR-549

    Well-Known Member

    Sep 22, 2013
    2,004
    394
    I would have thought that the low density would limit the current.
     
  7. #12

    Expert

    Nov 30, 2010
    16,340
    6,824
    7.6 Henries at 240 V and 50 Hz will limit the current to .1 amp.
    Xl = 2PiFL
     
Loading...