Paschen curve

Fig. 9.18 Breakdown voitage U between paraiiei eiectrodes in a homogeneous eiectricai fieid as a function of gas pressure p distance between eiectrodes d (in mm) (Paschen curve), for air.

The conditions for gas breakdown in an electrical field can be described in terms of the breakdown voltage as a function of the product of pressure and gap spacing. The resulting graph is known as the Paschen curve... 

Figure 5 Paschen curve in atmospheric air, comparing simulation results with and without field emission, with experimental results (Zhang et al., 2004a reproduced with permission).

In other words, if M 11. This relation allows the determination of the breakdown voltage of the system, as given by the Paschen curve. 

Townsend Mechanism of Electric Breakdown and Paschen Curves... 

Here C = In - lnln( - -1) is almost constant. The breakdown voltage dependence on the similarity parameter pd is usnally referred to as the Paschen curve (Fig. 4-2 Raizer,... 

Plasma parameters move to the left side of the Paschen curve (Section 4.1.1). The Paschen minimum is aboutpd=3cvci- Torr for some gases therefore, a 30- xm gap at 1 atm corresponds to the left-hand side of the curve. 

FIGURE 1.5 Paschen curves for N2, H2, and air. (From Cobine, J.D., Gaseous Conductors, Dover, 1941.)... 

Figure 19.4. Paschen curves for air, nitrogen and sulfur hexafluoride from Husain, E. and Nema, R.S. - Analysis of the Paschen curves for air, N2, SF using the Townsend breakdown equation IEEE Transactions El-17 (4) 350-353. Copyright 1982 IEEE and used with permission.

Dark space shield (plasma) A grounded surface that is placed at less than a dark space width from the cathode in order to prevent establishing a discharge in the region between the two surfaces. Also called the Ground shield. See also Paschen curve. 

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