TEMPEST amplitude inversion plots about hiqga.jl

[a2ray]

very nice, closed by c8887e1

[NMoghaddam]

Items to do in the TEMPEST1DInversion.jl

• write a function that returns sigma, fm and d as in lines 308 - 311
• add an if statement to use the function when we want to use vector sum and plot f against d in line 388

To review the steps for doing the inversion, refer to the notes for TEMPEST inversion under Examples > tempest > amponly

[NMoghaddam]

Two functions called get_fm and get_dSigma added to the TEMPEST1DInversion.jl to handle switching the flag for vectorsum in order to plot sqrt.(Bx.^2 + Bz.^2).

The first image shows the Bx and Bz components of Bfield individually when the vectorsum= false.
The second image shows the sqrt.(Bx.^2 + Bz.^2) when the vectorsum = true.