# Saltation and Particle Charge Polarity

**URL:** <https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443>\
**Category:** Uncategorized\
**Created:** [April 21, 2025, 12:17am UTC](https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443 "2025-04-21T00:17:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![SandmanWx](https://yyz2.discourse-cdn.com/free1/user_avatar/vapor.discourse.group/sandmanwx/32/205_2.png) [@SandmanWx](https://vapor.discourse.group/u/SandmanWx)\
**Post date:** [April 21, 2025, 12:17am UTC](https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443/1 "2025-04-21T00:17:41Z")

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[Particle Renderer — 3.9.3 documentation](https://ncar.github.io/VaporDocumentationWebsite/vaporApplicationReference/particleRenderer.html)  
Does the LPT also keep track of charge polarity of dust particles?  
Or of graupel particle charge polarity?  
And of the effects of static electric fields?

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**Author:** ![pearse](https://yyz2.discourse-cdn.com/free1/user_avatar/vapor.discourse.group/pearse/32/177_2.png) [@pearse](https://vapor.discourse.group/u/pearse)\
**Post date:** [April 22, 2025, 4:07pm UTC](https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443/2 "2025-04-22T16:07:26Z")

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Hi, the particle renderer can show any variables that are defined in your Data Collection Particles (DCP) dataset. If you add scalar variables for charge polarity similar to what’s shown for the speed variable in the documentation link you’ve posted, VAPOR will be able to render them. Note that we are not simulating these effects in VAPOR. We are just showing what is represented in the data itself.

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**Author:** ![SandmanWx](https://yyz2.discourse-cdn.com/free1/user_avatar/vapor.discourse.group/sandmanwx/32/205_2.png) [@SandmanWx](https://vapor.discourse.group/u/SandmanWx)\
**Post date:** [July 13, 2025, 10:24pm UTC](https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443/3 "2025-07-13T22:24:13Z")

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I would like to see a feature like that which considers the effects of E-fields on particle flow.

Aggregate fragmentation of saltation, the charge generation existing in the suspension, interaction with the LPCR of the tripole charge structure of thunderstorms.

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**Author:** ![pearse](https://yyz2.discourse-cdn.com/free1/user_avatar/vapor.discourse.group/pearse/32/177_2.png) [@pearse](https://vapor.discourse.group/u/pearse)\
**Post date:** [July 18, 2025, 7:13pm UTC](https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443/4 "2025-07-18T19:13:39Z")

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Right. In the example docs, we have a scalar field for “speed” that gets assigned to each particle. The scalar variables like aggregate fragmentation of saltation would need to be added to your file in the same way. Does that make sense?

```auto
 netcdf particles_000 {
 dimensions:
         P = 200 ;
         T = UNLIMITED ; // (1 currently)
         axis = 3 ;
 variables:
         double T(T) ;
                 T:units = "seconds" ;
         float Position(T, P, axis) ;
         float vel(T, P, axis) ;
         float speed(T, P) ;
 }

```

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<div class="post-metadata">

**Author:** ![SandmanWx](https://yyz2.discourse-cdn.com/free1/user_avatar/vapor.discourse.group/sandmanwx/32/205_2.png) [@SandmanWx](https://vapor.discourse.group/u/SandmanWx)\
**Post date:** [July 21, 2025, 10:37am UTC](https://vapor.discourse.group/t/saltation-and-particle-charge-polarity/443/5 "2025-07-21T10:37:00Z")

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Yes. I will have to work with this to see what kind of output it can generate.