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Dear Users,
The charge of all but hydrogen ion species, as seen by the PIC
algorithm, was wrong *after ionizing an atom/ion*.
Accidentally, the charge state inside our `GetCharge` trait was
calculated as
```
proton number * ( proton number - bound electrons)
```
instead of
```
proton number - bound electrons
```
in case `chargeRatio` of the species in `speciesDefinition.param` was
different from `1.0` (we usually set it to the fully ionized species'
charge density).
**Affected Setups**
If *all of the following criteria* are true for at least one of your ion
species, your simulation is affected:
- your species in `speciesDefinition.param` used an `ionizer`
- your species is not hydrogen
- your species moves and/or creates currents (pusher, current solver)
- you defined `chargeRatio` for that species different from `1.0`
- you are using the latest stable release (0.2.3) or older
Pre-ionized setups without ionization physics are unaffected.
**Implications**
The following quantities were falsely calculated:
- plasma dynamics (pusher used wrong charge to mass ratio,
current solver used wrong charge)
- outputs to files (`fields/<species>_chargeDensity`)
Note that the wrong plasma dynamics resulting from that highly
overcharged ion species is a severe bug and will likely render the
complete simulation unphysical if the above mentioned criteria are met.
**Kudos**
Thanks to Thomas Kluge for reporting the issue.
**Reference**
https://github.com/ComputationalRadiationPhysics/picongpu/pull/1844
**Fixes**
- the bug is fixed in `dev` since #1844 was merged yesterday
- the bug will be fixed in a 0.2.4 release for "stable"
Best regards,
Axel Huebl
--
Axel Huebl
Phone +49 351 260 3582
https://www.hzdr.de/crp
Computational Radiation Physics
Laser Particle Acceleration Division
Helmholtz-Zentrum Dresden - Rossendorf e.V.
Bautzner Landstrasse 400, 01328 Dresden
POB 510119, D-01314 Dresden
Vorstand: Prof. Dr.Dr.h.c. R. Sauerbrey
Prof. Dr.Dr.h.c. P. Joehnk
VR 1693 beim Amtsgericht Dresden
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