Return-Path: Received: from mx2.fz-rossendorf.de ([149.220.142.12] verified) by hzdr.de (CommuniGate Pro SMTP 6.1.9) with ESMTP id 14021713 for picongpu-users@cg.hzdr.de; Wed, 04 May 2016 13:26:07 +0200 Received: from localhost (localhost [127.0.0.1]) by mx2.fz-rossendorf.de (Postfix) with ESMTP id F296A45611 for ; Wed, 4 May 2016 13:26:06 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mx2.fz-rossendorf.de Received: from mx2.fz-rossendorf.de ([127.0.0.1]) by localhost (mx2.fz-rossendorf.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id u_uCY7VQStb2 for ; Wed, 4 May 2016 13:25:57 +0200 (CEST) Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=147.231.234.10; helo=mailgw.eli-beams.eu; envelope-from=prvs=1932e0d5c7=danila.khikhlukha@eli-beams.eu; receiver=picongpu-users@hzdr.de Received: from mailgw.eli-beams.eu (mailgw.eli-beams.eu [147.231.234.10]) by mx2.fz-rossendorf.de (Postfix) with ESMTPS id 517B74560C for ; Wed, 4 May 2016 13:25:57 +0200 (CEST) Received: from braun.eli-beams.eu ([10.1.5.17]) by mailgw.eli-beams.eu with ESMTP id u44BPu09004784-u44BPu0B004784 (version=TLSv1.0 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 4 May 2016 13:25:56 +0200 Received: from BRAUN.eli-beams.eu ([::1]) by braun.eli-beams.eu ([::1]) with mapi id 14.03.0279.002; Wed, 4 May 2016 13:25:56 +0200 From: Khikhlukha Danila To: "picongpu-users@hzdr.de" Subject: RE: [PIConGPU-Users] laserGaussianBeam initialization Thread-Topic: [PIConGPU-Users] laserGaussianBeam initialization Thread-Index: AQHRpe4bakln6nCIXUi7caqzCWxvOp+oo1Px Date: Wed, 4 May 2016 11:25:55 +0000 Message-ID: References: In-Reply-To: Accept-Language: en-US, cs-CZ Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.36.30.5] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Thanks, Axel,=0A= now it is absolutely clear.=0A= =0A= Cheers,=0A= Danila.=0A= ________________________________________=0A= From: picongpu-users@hzdr.de [picongpu-users@hzdr.de] on behalf of Huebl, A= xel [a.huebl@hzdr.de]=0A= Sent: Wednesday, May 04, 2016 12:17 PM=0A= To: picongpu-users@hzdr.de=0A= Subject: Re: [PIConGPU-Users] laserGaussianBeam initialization=0A= =0A= Dear Danila,=0A= =0A= yes you got that correctly.=0A= =0A= The line=0A= =0A= const double PULSE_LENGTH_SI =3D 5.0e-15; //25.0e-15 / 1.17741;=0A= =0A= are confusing comments behind "//" and are *outdated*. I will remove=0A= those for the next release.=0A= =0A= Thanks!=0A= Axel=0A= =0A= On 04.05.2016 11:45, Khikhlukha Danila wrote:=0A= > Dear Axel,=0A= > thank you for your replay and clarification!=0A= >=0A= > Indeed I'm using release-0.1.2 version. So just to double check let me re= peat your answer.=0A= > So PULSE_LENGHT in the laserConfig.param file is the intensity sigma. Whi= ch means that for 25fs of intensity FWHM, PULSE_LENGHT =3D 25fs/k, where k = =3D 2*sqrt(2*log(2))=3D2.3548. So PULSE_LENGHT =3D 10.616fs. This matches y= our answer and comments in the code. However, there is a line=0A= > 60 const double PULSE_LENGTH_SI =3D 5.0e-15; //25.0e-15 / 1.= 17741;=0A= > which is a bit confusing, cause I don't understand the number 1.1774 (and= 25.0e-15 / 1.17741 will not give 5.0e-15).=0A= > I'm sorry for being picky however I just want to have a clear picture of = the initialization procedure and reading the comments is a good way to get = familiar with unknown code.=0A= >=0A= > Once again thanks for your support!=0A= >=0A= > Cheers,=0A= > Danila.=0A= > ________________________________________=0A= > From: picongpu-users@hzdr.de [picongpu-users@hzdr.de] on behalf of Huebl,= Axel [a.huebl@hzdr.de]=0A= > Sent: Wednesday, May 04, 2016 11:05 AM=0A= > To: picongpu-users@hzdr.de=0A= > Subject: Re: [PIConGPU-Users] laserGaussianBeam initialization=0A= >=0A= > Dear Danila,=0A= >=0A= >=0A= > we cross-checked our implementation and it looks correct.=0A= > We will reference the full derivation in our wiki in the next days.=0A= >=0A= > To give you a non-latex explanation for now:=0A= >=0A= > *laserConfig.param*=0A= > defined in laserConfig.param you found correctly the variable=0A= > "PULSE_LENGHT" which is as described the sigma of a standard gaussian of= =0A= > the intensity.=0A= > (For the experimentalist conversion to FWHM of intensity, see conversion= =0A= > factor in the comment.)=0A= >=0A= > *laserGaussianBeam.hpp*=0A= > In the implementation (great you found it on your own! :) ) we set the= =0A= > electric field.=0A= >=0A= > the relation of electric field and intensity sigma's are:=0A= > sig_Ex^2 =3D 2 sig_I^2 | * 2=0A= > 2 sig_Ex^2 =3D 4 sig_I^2=0A= >=0A= > So instead of converting into sig_Ex by sqrt(2) we just implemented=0A= > ( 2 sig_I) ^ 2 =3D=3D 4 sig_I^2=0A= >=0A= > for setting the E-field component.=0A= >=0A= >=0A= > Cheers,=0A= > Axel=0A= >=0A= > On 03.05.2016 19:42, Huebl, Axel wrote:=0A= >> Hi Danila,=0A= >>=0A= >> thanks for the question!=0A= >>=0A= >> Which version of PIConGPU you are using?=0A= >> The latest release, 0.1.2, changed the documentation in the=0A= >> laserConfig.param a bit because it was not precise before it.=0A= >>=0A= >>=0A= >> I got your question regarding the temporal envelope (pulse length) of=0A= >> the Gaussian Beam. I actually just fixed it for 2D last year but we can= =0A= >> double check tomorrow if the documentation is up-to-date.=0A= >>=0A= >> https://github.com/ComputationalRadiationPhysics/picongpu/pull/1090=0A= >>=0A= >> So far, great you found the implementation yourself! :) I am missing the= =0A= >> sqrt on the first view, too but let us check tomorrow.=0A= >>=0A= >>=0A= >> Cheers,=0A= >> Axel=0A= >>=0A= >> On 02.05.2016 13:06, Khikhlukha Danila wrote:=0A= >>> Hi=0A= >>> all,=0A= >>>=0A= >>>=0A= >>>=0A= >>> I have a couple of short questions regarding the Gaussian beam=0A= >>> initialization.=0A= >>>=0A= >>>=0A= >>> 1. As far as I understood from the code comments=0A= >>> (simulation_defines/param/laserConfig.param)=0A= >>> the initialization for laser pulse is done based on the sigma of the=0A= >>> intensity envelope. However in the code=0A= >>> (src/picongpu/include/fields/laserProfiles/laserGaussianBeam.hpp) it=0A= >>> looks like PULSE_LENGTH is the sigma of electrical field envelope.=0A= >>> I also wasn't able to find any conversion (namely=0A= >>> sqrt(2))=0A= >>>=0A= >>>=0A= >>> 2. So at the moment I'm assuming that the initialization of the Gaussia= n=0A= >>> beam is done based on the sigma of an electrical field envelope.=0A= >>> So if we consider k =3D 2*sqrt(2*log(2))=3D2.3548 as a coefficient betw= een=0A= >>> FWHM and sigma of the Gaussian curve=0A= >>> then the coefficient between sigma of an electrical field and FWHM of= =0A= >>> the intensity becomes sqrt(2)/k =3D 0.6006.=0A= >>> However, in comments for laserGaussianBeam it is stated the number=0A= >>> 1./1.17741 =3D 0.8493 and I'm not sure what is it.=0A= >>>=0A= >>>=0A= >>> Can you please double check if comments are up-to-date? Otherwise I got= =0A= >>> something wrong in the description.=0A= >>>=0A= >>>=0A= >>> Thank=0A= >>> you,=0A= >>>=0A= >>> Danila.=0A= >>=0A= >=0A= > --=0A= >=0A= > Axel Huebl=0A= > Phone +49 351 260 3582=0A= > https://www.hzdr.de/crp=0A= > Computational Radiation Physics=0A= > Laser Particle Acceleration Division=0A= > Helmholtz-Zentrum Dresden - Rossendorf e.V.=0A= >=0A= > Bautzner Landstrasse 400, 01328 Dresden=0A= > POB 510119, D-01314 Dresden=0A= > Vorstand: Prof. Dr.Dr.h.c. R. Sauerbrey=0A= > Prof. Dr.Dr.h.c. P. Joehnk=0A= > VR 1693 beim Amtsgericht Dresden=0A= >=0A= >=0A= > #############################################################=0A= > This message is sent to you because you are subscribed to=0A= > the mailing list .=0A= > To unsubscribe, E-mail to: =0A= > To switch to the DIGEST mode, E-mail to = =0A= > To switch to the INDEX mode, E-mail to =0A= > Send administrative queries to =0A= >=0A= =0A= --=0A= =0A= Axel Huebl=0A= Phone +49 351 260 3582=0A= https://www.hzdr.de/crp=0A= Computational Radiation Physics=0A= Laser Particle Acceleration Division=0A= Helmholtz-Zentrum Dresden - Rossendorf e.V.=0A= =0A= Bautzner Landstrasse 400, 01328 Dresden=0A= POB 510119, D-01314 Dresden=0A= Vorstand: Prof. Dr.Dr.h.c. R. Sauerbrey=0A= Prof. Dr.Dr.h.c. P. Joehnk=0A= VR 1693 beim Amtsgericht Dresden=0A= =0A=