magnetic screens surrounding central magnetic pole and discharge channel, a variation of length of internal and external magnetic screens provides necessary positive gradient of magnetic field in anode area and in {HEAD ~ most part} of {TAIL ~ discharge channel} for efficient ionization and suppression of oscillations of discharge current and voltage, 
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magnetic screens surrounding central magnetic pole and discharge channel , a variation of length of internal and external magnetic screens provides necessary positive gradient of magnetic field in anode area and in { HEAD ~ most part } of { TAIL ~ discharge channel } for efficient ionization and suppression of oscillations of discharge current and voltage ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH