In 2001, Aplate = 0.16 m2, C = 0.5 gF, Gamp = 1, and Gplc = 1. According to the
manufacturer specifications, Glink = 1, however this will be considered a nominal value
since in practice Glink is often not unity. In addition, the value for C varied between
individual electric field measurements, hence C = 0.5 rF is also considered a nominal
value. Therefore, the nominal voltage seen at the input of the scope for the 2001 MSE
electric field measurements is given by
scope-nom(t) = (2.83 x 106) Enorm(t) (3-61)
Vscope-nom(t) is expressed in units of V when Enorm(t) is expressed in units of
V m1. If ,scope-nom(t) = 1 V and the above expression is solved for Enorm(t), then
Enorm = 3.53 x 105 Vm1 V1 (3-62)
If Enorm is expressed in units of kV m1, then the above expression becomes
Enorm = 353 kV m1 V1 (3-63)
Thus, nominally, one volt present at the input of the digitizer corresponds to an
electric field magnitude of about 350 kV m1.
In 2002, Aplate = 0.16 m2, C = 0.2 kF, Gamp = 2, and Gpc = 1. If, as before, Glink
is assumed to have a nominal value of unity, the nominal voltage seen at the input of
the scope for the 2002 MSE electric field measurements is
Vscopenom(t)= (1.42x 10 5)Enorm(t) (3-64)
Again, solving the equation for Enorm, expressed in units of kV m1, yields
Enorm = 70.6 kV m1 V 1 (3-65)
If the true capacitor value for each electric field measurement is substituted into
Equation 3-60, the expression for the electric field as a function of the voltage at the