Negative corona discharges

There are, however, also similarities between the two discharge types. Positive ions drifting toward the opposite electrode form a space charge that affects the electric field and the corona current principally in the same way as in a negative corona discharge. Also, the charging of particles takes place almost in the same way for both types of corona discharge. 

T. Khayamian, M. Tabrizchi and M.T. Jafari, Analysis of 2,4,6-trinitrotoluene, pentaerythritol tetranitrate and cyclo-1,3,5-trimethylene-2,4,6-trinitramine using negative corona discharge ion mobility spectrometry, Talanta 59(2) (2003) 327—333. 

Figure 12.9 Schematic diagram of negative corona discharge showing negative ion motion away from center electrode, positive ion motion toward center electrode.

Fig. 14. Threshold (initial) voltage (kV) of the negative corona discharge in a mixture of xenon with added O2, COj, N2 and air (vol %) at 500 torr ...

D. Skalny, J. Orszagh, S. Matejcik, N.J. Mason, Ozone generation in positive and negative corona discharge fed by humid oxygen and carbon dioxide. Phys. Scr. T131, 1-3 (2008)... 

APCI is a well-known technique for ionizing explosive molecules. A high voltage of about -2 kV is applied to a needle electrode to produce a negative corona discharge. The typical ionization process of the explosive molecules (M) consists of two steps ... 

Negative corona is considerably more complicated and depends more on the emission properties of the discharge surface and of the gas. White (W4) gives a detailed discussion of corona mechanisms. In general, the negative corona threshold is higher than the positive. 

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