How to output electron density?

[zhangxinyao999]

Hi!

I'm interested in the density distribution of plasma in the free space transport simulation, but I can't find any sample code.

Can you tell me how to solve this problem?

Thank you!

[chrisbrahms]

Hi!

Unfortunately we haven't had time to implement statistics for the free-space simulation cases yet, which is why there is no sample code.

You can extract it from the output field using the following code:

##
import FFTW
Etr = FFTW.irfft(q \ output["Eω"], length(grid.t), 1) # transform from E(ω, k, z) to E(t, r, z)

ionpot = PhysData.ionisation_potential(gas) # ionisation potential
ionrate = Ionisation.ionrate_fun!_PPTcached(gas, λ0) # ionisation rate function

ionfrac = Ionisation.ionfrac(ionrate, Etr, grid.t[2]-grid.t[1]) # ionisation fraction at each (t, r, z)

ionfrac_end = ionfrac[end, :, :] # ionisation fraction at the end of the time window

##
plt.figure()
plt.pcolormesh(zout*1e2, q.r*1e3, ionfrac_end)
plt.xlim(1e2L/2 .+ [-5, 5])
plt.ylim(0, 0.1)
plt.xlabel("Distance (cm)")
plt.ylabel("Radial position (mm)")
plt.colorbar(label="Ionisation fraction")

Note that I've assumed the existence of a few variables here--see the radial.jl example file for their meanings. This produces a plot which looks like this (for the radial.jl example with 200 μJ of energy, when the output contains 501 z points):

Running this code takes a while, because the inverse transform of the whole output is quite a lot of work. But it should get you the output you need, I hope.

[zhangxinyao999]

Thanks! I am now looking at the code about tunnel ionization(ADK model) in Luna. I found something that puzzled me.

In https://github.com/LupoLab/Luna.jl/blob/master/src/Ionisation.jl, the formula of ADK rate do not have a term $g{lm}$, which is different for different materials. In this book, Zenghu Chang: Fundamentals of Attosecond Optics (2011) p. 181,182. Helium: $G{lm}=1$, Neon: $G{lm} = 3$. So, I don't understand why there is no this term $G{lm}$.

Besides, the calculate of this term cn_sq, I wonder why it don't consider $l$. Also in that book, this term is

Is this an approximation because $l^{*}$ is small compared with $n^{*}$?