how to define density as any function

[amarsarari]

How to define density in term of exponential function like ne=den_H exp((x - 70.0micron) / (5*micron)) i am unable to it in input deck can u help me

[Status-Mirror]

Hey @amarsarari

You cant write equations in the input deck, using syntax which can be read by the maths parser.

In your example, you could define an exponential density in the species block using commands like this:

begin:species
   name = Electron
   charge = -1.0
   mass = 1.0
   frac = 0.5
   density = 1.0e20 * exp((x - 70.0e-6) / 5.0e-6)
   density = if(x gt 70.0e-6, 1.0e20, density(Electron))
end:species

In this example, the electron number density rises from $1.0\times 10^{20}m^{-3}\exp((x_{min}-70.0e-6)/5.0e-6)$ on the x_min boundary, to $1.0\times 10^{20} m^{-3}$ for $x>70\mu m$.

Hope this helps, Stuart

[amarsarari]

Thank you sir

On Fri, 23 Jun 2023, 13:22 Stuart Morris, @.***> wrote:

Hey @amarsarari https://github.com/amarsarari

You cant write equations in the input deck, using syntax which can be read by the maths parser https://epochpic.github.io/documentation/code_details/maths_parser.html.

In your example, you could define an exponential density in the species block https://epochpic.github.io/documentation/input_deck/input_deck_species.html using commands like this:

begin:species name = Electron charge = -1.0 mass = 1.0 frac = 0.5 density = 1.0e20 * exp((x - 70.0e-6) / 5.0e-6) density = if(x gt 70.0e-6, 1.0e20, density(Electron)) end:species

In this example, the electron number density rises from $1.0\times 10^{20}m^{-3}\exp((x_{min}-70.0e-6)/5.0e-6)$ on the x_min boundary, to $1.0\times 10^{20} m^{-3}$ for $x>70\mu m$.

Hope this helps, Stuart

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[amarsarari]

Hi sir i want 1.0e20 exp((x - 10.0e-6) / 2.0e-6) from 0 to 10 micron then 1.0e20 from 10 to 5 micron then rising from 1.0e20 exp((15.0e-6-x) / 5.0e-6) from 15 to 25 micron how I can do plz help me