When low-field conditions no longer prevail, the ion mobility itself becomes a function of the electric field strength which is usually described empirically through the so-called alpha function.
32.
Acceleration ( meters per second per second ) trots off the tongue easily enough-but electric field strength ( meter kilogram per second per second per second per amp ) does not!
33.
This happens when the electric field strength exceeds the dielectric strength of the air, about 30 kV per centimeter, and occurs first at sharp points and edges on the high voltage terminal.
34.
In the case of a GM tube the high electric field strength is sufficient to cause complete ionisation of the fill gas surrounding the anode from the initial creation of just one ion pair.
35.
Tests included measuring an internal beam of electrons, comparing the machine with and without a magnetic field, measuring the voltage at different locations and comparing voltage changes to the magnetic and electric field strength.
36.
The text also states that, " . . . over most of the area affected by the EMP the electric field strength on the ground would exceed 0.5 " E " max.
37.
Although air is normally an excellent insulator, when stressed by a sufficiently high voltage ( an electric field strength of about 3 x 10 6 electrical spark or an electric arc that bridges the entire gap.
38.
The breakdown voltage is critically affected by factors such as the geometry of the capacitor conductive parts; sharp edges or points increase the electric field strength at that point and can lead to a local breakdown.
39.
The narrow slit width not only enables the capillary feed, but, when combined with the sharp channel edges directly opposite the accelerator, also ensures that a high electric field strength is obtained near the slit exit.
40.
Any non-linearity in electric field strength as alluded to by Gr8xoz has no relavence to your assignment question, because you want the breakdown initiating voltage, which is under conditions existing just before breakdown actually occurs.
