picongpu-users@hzdr.de Mailing List Archive

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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