# Tri-Maxwellian Plasma Environment

**URL:** <https://forum.spis.org/t/tri-maxwellian-plasma-environment/1175>\
**Category:** SPIS\
**Created:** [15 March 2023 13:35 UTC](https://forum.spis.org/t/tri-maxwellian-plasma-environment/1175 "2023-03-15T13:35:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![agozutok](https://forum.spis.org/letter_avatar_proxy/v4/letter/a/67e7ee/32.png) [@agozutok](https://forum.spis.org/u/agozutok)\
**Post date:** [15 March 2023 13:35 UTC](https://forum.spis.org/t/tri-maxwellian-plasma-environment/1175/1 "2023-03-15T13:35:47Z")

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Dear all

Hi, I would like to implement the plasma popultion inputs for a scenario with more than 2 populations for electrons (actually 3 populations for low, mid & high energy spectra).

I tried to modify the global parameters tab by adding 3rd population plasma properties such as density, velocity, temperature etc., however, I ended up with my scenarios running with only two electron populations.

I actually use the software version 6.1.0, how can I modify the global parameters tab to run tri-Maxwellian plasma environment?

Best Regards

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**Author:** ![SachinReddy7](https://forum.spis.org/letter_avatar_proxy/v4/letter/s/f0a364/32.png) [@SachinReddy7](https://forum.spis.org/u/SachinReddy7)\
**Post date:** [3 July 2023 16:32 UTC](https://forum.spis.org/t/tri-maxwellian-plasma-environment/1175/2 "2023-07-03T16:32:02Z")

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Did you manage to sort this out? You can use the “Pop1…” settings to add another population. I am trying to add a 3rd population of electrons but I can’t get it to work as yet – would love to know if you cracked it.

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**Author:** ![frejon](https://forum.spis.org/letter_avatar_proxy/v4/letter/f/7feea3/32.png) [@frejon](https://forum.spis.org/u/frejon)\
**Post date:** [7 July 2023 10:03 UTC](https://forum.spis.org/t/tri-maxwellian-plasma-environment/1175/3 "2023-07-07T10:03:49Z")

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Hi guys, did you follow the user manual? found at /documentation/DocSpisNum/SPIS-6-DDD\_2.4.pdf, or via the index.html documentation.

> SPIS V6 USER MANUAL AND DETAILED DESIGN DOCUMENT -121-  
> Plasma environment4.6  
> General overview4.6.1  
> […] By default, the environment is defined (via the “environmentType” parameter) as a  
> “BiMaxwellianEnvironment” which limits the population to the four above-mentioned ones. In order to use more population, one has to set the environment description to “ExtendedEnvironment”. In this case, the number of supplementary population must be specified by the “ExtendedPopNbr” parameter, and the characteristics of the populations be defined using the same parameters than previously, setting popX with X the population number (starting at 1).

i.e. you have to change the environmentType, add the parameter ExtendedPopNbr, set it to e.g. 1 and set the corresponding values for pop1