example “bremsstrahlung"

[baobaba13]

I ran the calculation example “bremsstrahlung" provided by picongpu, and used paraview to post process the .h5 file of the analog output, and got the results as shown in the figure below. I suspect the results are incorrect, because they are inconsistent with the results shown in the paper, especially the photon energy density is empty. I don't know where the problem is. Thank you very much for giving me some guidance.

1. data/5000/fields/e_all_chargeDensity
2. data/5000/fields/E/X 3.data/5000/fields/ph_all_chargeDensity and data/5000/fields/ph_all_energyDensity

[steindev]

@baobaba13 have you checked earlier time steps as well? I do not know the Bremsstrahlung example, but I assume it is very small as it is an example. The photons may have left the simulation volume already.

[baobaba13]

@steindev Yes, I have also checked the early time steps, and the results are all 0. I try to set the parameters the same as those in the literature, but there is still no consistent result with those in the literature

[steindev]

Sry for the late reply. I am confused. Did you run the example without any changes or only with parameters stated in the 'literature'? What literature do you actually refer to?

[baobaba13]

Hi @steindev The literature I refer to is Entwicklung und Ü berpr ü Fung eines photoenmodels f ü r die abstractlung durch hochenergetische elektronen , which is [https://picongpu.readthedocs.io/en/latest/examples/Bremsstrahlung/README.html]mentioned in the website. I have seen the parameters set in the example in the mentioned literature, but they are not the same as the parameters mentioned in the literature. I run the simulation according to the parameters set in the example

[steindev]

Hi @baobaba13 I need to forward this to @PrometheusPi since he supervised the developments back then. Unfortunately, he is unavailable till September. But I have zero experience with this feature.

[steindev]

Ping @PrometheusPi

[PrometheusPi]

@steindev Thanks for pinning. Totally oversaw this issue.

@baobaba13 Thanks for reporting and sorry for taking that long. This looks like a serious issue. I suspect that no photons are created. I assume you used either the 1.cfg or 8.cfg for the setup. In both cases, there are two photon specific outputs:

• the photon energy histogram
• the photon calorimeter Could you please tell be, what the first and last row of the photon histogram file is? Furthermore, what does h5ls -r or bpls -r returns when applied to the calorimeter output?

In parallel I will try to run the example on out machine.

If I remember correctly Heiko mentioned something of disabling the photon generation and writing them directly to the calorimeter. But a quick look through the code didn't reveal such a part of the code - but I will look further.

[PrometheusPi]

@baobaba13 Could you already check your output files. I am sorry, I so far had no time to run the simple test case.

[PrometheusPi]

@baobaba13 we removed Bremsstrahlung and synchrotron radiation with #4395 due to its outdated dependencies. If you want to use it, please use release 0.6.0 or older.

[steindev]

@baobaba13 are you actually still interested in this issue? Please drop a line here if so, otherwise this issue will be closed in the near future.

[PrometheusPi]

I will close this issue now. If you want to further investigate it, please reopen the issue.