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Exactly, every direction (plane) that is not set to --periodic is
automatically absorbing (open).
The only exception is the laser initialization plane, which activates
it's absorbers after the LASER_INIT time has passed.
Nevertheless, our open boundary conditions are rather rough and
"stupid", adding PMLs there would be wonderful.
Axel
On 09.02.2017 16:11, Khikhlukha Danila wrote:
> Hi Richard,
>
> Just to double check, I guess currently the boundary conditions for both
> particles and fields are open, i.e. absorbing?
>
>
>
> Regards,
>
> Danila.
>
>
>
> *From:*picongpu-users@hzdr.de [mailto:picongpu-users@hzdr.de] *On Behalf
> Of *Richard Pausch
> *Sent:* Wednesday, February 08, 2017 12:55 PM
> *To:* picongpu-users@hzdr.de
> *Subject:* Re: [PIConGPU-Users] [PIConGPU-Users] [PIConGPU-Users]
> [PIConGPU-Users] [PIConGPU-Users] [PIConGPU-Users] Laser pulse polarization
>
>
>
> Dear Bifeng Lei,
>
> thanks for the new plots. They helped me a lot.
>
> I suspect that your laser is partially reflected at the boundaries.
> - Do you have “our” absorbing boundary conditions on? (No "—periodic 1
> 0 1" in submit.start)
> - Is your transversal simulation length not much larger than your laser
> spot-size? (cells in x |CELL_WIDTH_SI| / |W0_SI| > ~10 and cells in z
> |CELL_DEPTH_SI| / |W0_SI| > ~ 10)
>
> If you answer both questions with yes, you might get some reflections
> from the absorber that interacts with the (back) of you laser pulse.
>
> To avoid this, increase the transversal extent to contain more than
> approximately 10-20 laser spot sizes.
>
> I hope this will solve your problem.
>
> Best,
> Richard
>
>
> Am 08.02.2017 um 12:06 schrieb Bifeng Lei:
>
> Dear Richard,
>
> I am not reduce the resolution. by setting |plt.imshow( ... ,
> interpolation="nearest"|)
>
> A 1D lineout plot on-axis.
>
> All best
> Bifeng Lei
>
> On 02/08/2017 11:50 AM, Richard Pausch wrote:
>
> Hi Bifeng Lei,
>
> Okay - that looks fine (except that you time step is a bit short
> for numerical stability in long simulation runs, better would be
> ~1.12969e-16).
>
> Why does your picture only show one “imshow cell”/colored cell
> per ~10-50 cells?
> Did you reduce the resolution during analysis?
> Might the transversal structures we see in the picture be an
> aliasing effect? (can be avoided by setting |plt.imshow( ... ,
> interpolation="nearest"|)
>
> Could you please re-plot the picture in 1D, be selecting the
> center x-position and plotting a lineout of the field along the
> y-axis with a mark for each value. That would ease determining
> if there are aliasing effects in the imshow picture.
>
> Best,
> Richard
>
> Am 08.02.2017 um 11:37 schrieb Bifeng Lei:
>
> Dear Richard,
>
> Thank you so much for your reply.
>
> A 0.8um laser is used. The resolution is given as:
>
> dx and dz: 0.0743e-6m --> 0.8/0.0743=10.7
>
> dy: 0.0443e-6m --> 0.8/0.0443=18
>
> dt : 3.0e-17s
>
> By the way, is there a way to set the polarization angle
> with respect to x/z-axis?
>
> All best
>
> Bifeng Lei
>
>
>
> On 02/08/2017 11:28 AM, Richard Pausch wrote:
>
> longitudinal resolution is too low?
>
>
>
> With best regards,
>
> Ph.D Bifeng Lei
>
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Axel Huebl
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Computational Radiation Physics
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