high voltage igniter for carbon arc lamp
Already been done. See PDF for diagram [PDF]


  The problem: Striking a carbon arc requires ionization of the gap by
  mechanically reducing gap size, auxiliary starting electrodes,
  ultraviolet radiation, or "seeding" the gap to lower the required
  ionization potential. The mechanical method risks electrode contact
  and resultant contamination plus erosion. The other methods require
  complicated equipment. The solution: Inserting a high-voltage,
  low-current pulse in series with the arc power supply. This auxil-
  -iary supply efficiently ignites the arc and is easily and economically produced. How it's done: An inductor is placed in the
  negative line between the arc power supply and the negative electrode
  (tungsten rod). An auxiliary high-voltage, low-current igniting power
  supply charges the capacitor to provide the igniting pulse to the
  inductor. The arc power supply is turned on-about three seconds prior
  to the arc strike signal to ensure arc power at the electrodes when
  the igniting pulse arrives. The arc strike signal closes the relay,
  discharging the capacitor across the inductor. This applies the
  high-voltage pulse in series with the arc power supply ionizing the
  gap and igniting the arc. Notes:
  1. This circuit should be of use wherever arc burners, arc searchlights, or plasma jets are used.