Scale pedistal radius value by minor radius

The Fausser paper gives a_ped as 0.8 * A but the code currently just
uses the dimensionless value of 0.8. Scale this up by the minor radius
in the default input values to give the pedestal radius in metres.

Author: DanShort12

parametric_plasma_source/source_sampling.cpp

@@ -12,11 +12,11 @@ const double ion_density_origin = 1.09e+20;
 const double ion_temperature_pedistal = 6.09;
 const double ion_temperature_seperatrix = 0.1;
 const double ion_temperature_origin = 45.9;
-const double pedistal_radius = 0.8; // pedistal major rad
 const double ion_density_peaking_factor = 1;
 const double ion_temperature_peaking_factor = 8.06; // check alpha or beta value from paper
 const double minor_radius = 1.56; // metres
 const double major_radius = 2.5; // metres
+const double pedistal_radius = 0.8 * minor_radius; // pedistal minor rad in metres
 const double elongation = 2.0;
 const double triangularity = 0.55;
 const double shafranov_shift = 0.0; //metres