Received: from BRK2.fjfi.cvut.cz (147.32.9.22) by MRK2.fjfi.cvut.cz (147.32.9.23) with Microsoft SMTP Server (TLS) id 14.2.342.3; Mon, 22 Apr 2013 14:09:16 +0200 Received: from mailgw1.fjfi.cvut.cz (147.32.9.3) by BRK2.fjfi.cvut.cz (147.32.9.22) with Microsoft SMTP Server (TLS) id 14.2.342.3; Mon, 22 Apr 2013 14:09:15 +0200 Received: from mailgw1.fjfi.cvut.cz (localhost [127.0.0.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mailgw1.fjfi.cvut.cz (Postfix) with ESMTPS id E97CCC0068 for ; Mon, 22 Apr 2013 14:09:15 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by mailgw1.fjfi.cvut.cz (Postfix) with ESMTP id DB369C006A for ; Mon, 22 Apr 2013 14:09:15 +0200 (CEST) X-CTU-FNSPE-Virus-Scanned: amavisd-new at fjfi.cvut.cz X-CTU-FNSPE: this_is_mailgw_for_ctu_fnspe_header X-CTU-FNSPE-Helo: mail-qc0-f172.google.com X-CTU-FNSPE-Client-Address: 209.85.216.172 X-CTU-FNSPE-Client-Name: mail-qc0-f172.google.com X-CTU-FNSPE-Sender: markovic6453@gmail.com X-CTU-FNSPE-Recip: svoboda@fjfi.cvut.cz Authentication-Results: mailgw1.fjfi.cvut.cz (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from mailgw1.fjfi.cvut.cz ([127.0.0.1]) by localhost (mailgw1.fjfi.cvut.cz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DkHQnrnV6wvT for ; Mon, 22 Apr 2013 14:09:09 +0200 (CEST) Received: from mail-qc0-f172.google.com (mail-qc0-f172.google.com [209.85.216.172]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by mailgw1.fjfi.cvut.cz (Postfix) with ESMTPS id 85F94C0068 for ; Mon, 22 Apr 2013 14:09:08 +0200 (CEST) X-SenderID: Sendmail Sender-ID Filter v1.0.0 mailgw1.fjfi.cvut.cz 85F94C0068 Received: by mail-qc0-f172.google.com with SMTP id b25so2471514qca.17 for ; Mon, 22 Apr 2013 05:09:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:mime-version:in-reply-to:references:from:date:message-id :subject:to:content-type; bh=+NDbSE1Ff7YjP1zwcedRaxh4fgaJuxGdpH5OJaLogEM=; b=LSwqKbYn09uiO4f4goXu97Ngoryc5GfmwPR5jkFWwhxbB+Xwn64SupppaInE1vlMBI PifwEPQOCPRct/r7gZtXnGx6nKzMpP2gCBONFK9CbX5CAc/cRnnqsPogJ5bYxCOi918U 3LgSzdF0DbMREso0YkYJSGLt1fBrVFG/FPEcoiYP7ZSgWDtLKPZEIzqEmffS2HQQ209O NBs608KiGDmapIqsXTSs91K/d2pVDkRQ9kohFgbzTxR/oYm1Qd4GFEVkwEcceFbAu5q7 Gb6VyBwxTythMGxFv9PMygEpwEhcCA/0gTk8pJMN47IBkEmfDDbtq9doC1dtoRp9mRmf NEvA== X-Received: by 10.224.53.11 with SMTP id k11mr22092990qag.3.1366632546801; Mon, 22 Apr 2013 05:09:06 -0700 (PDT) Received: by 10.49.132.197 with HTTP; Mon, 22 Apr 2013 05:08:46 -0700 (PDT) In-Reply-To: <51751b16.43230f0a.18a8.2512SMTPIN_ADDED_BROKEN@mx.google.com> References: <51751b16.43230f0a.18a8.2512SMTPIN_ADDED_BROKEN@mx.google.com> From: Tomas Markovic Date: Mon, 22 Apr 2013 14:08:46 +0200 Message-ID: Subject: Re: Langmuir - Mirnov joint experiment To: =?ISO-8859-1?Q?R=E9fy_D=E1niel?= , "Vojtech Svoboda" , , Jana Brotankova , Content-Type: multipart/alternative; boundary="20cf306f73d87da1a104daf1ef63" Return-Path: markovic6453@gmail.com X-MS-Exchange-Organization-PRD: gmail.com Received-SPF: Neutral (BRK2.fjfi.cvut.cz: 147.32.9.3 is neither permitted nor denied by domain of markovic6453@gmail.com) X-MS-Exchange-Organization-AVStamp-Mailbox: MSFTFF;1;0;0 0 0 X-MS-Exchange-Organization-SenderIdResult: NEUTRAL X-MS-Exchange-Organization-AuthSource: BRK2.fjfi.cvut.cz X-MS-Exchange-Organization-AuthAs: Anonymous MIME-Version: 1.0 --20cf306f73d87da1a104daf1ef63 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable This idea to measure poloidal rotation by both probes and Mirnov coils simultaneously is not something we did on GOLEM before, so it is hard to tell how will it turn out. Currently, motivation is driven by the fact that some aspects of rotation detected by Mirnov coils surprisingly seem correspond to specific findings by rake probe -- namely to close-to-constant E_r field at plasma edge regions. The arrangement will need to be flexible. To succeed we need nice magnetic island of low m at plasma edge (or close to it) -- i.e. low B_tor and high I_p -- have there been successful rake probe measurements at such parameters? It will also take some time to find optimal parameters, but island tailoring can be arranged relatively easily. Also, rake probe should be inserted at the same time into plasma region while island is there -- however if perturbation of plasma by probe does not allow for existence of magnetic islands, two or more shots of same parameters would be necessary -- to get usable data and to confirm that velocity of rotation is reproducible. The latter is not trivial thought -- my recent findings are that magnetic islands on GOLEM accelerate their rotation in presence of external poloidal field used for control of plasma position. At least such are findings by magnetic diagnostics, how is it for probes is not known to me -- we can investigate on-site. Gomtraic experiments up till now did not use plasma position control, but we will probably need to use horizontally-oriented poloidal field to prevent motion of plasma during experiment for better interpretation of data. However, this might have some impact on signal of islands -- it seemed to me that islands from when plasma is left alone to do what it wants were more stable than those detected with stabilisation winding on... Basically, we will need 1-2 days (depending on how machine will cooperate). First, discharge parameters will need to be found where nice and reproducible island at plasma edge (i.e. known r coordinate) is present -- as well as to identify time of its occurence. Reproducible island will also enable to investigate, whether plasma rotation changes between shots of same parameters. Then probe can be inserted into plasma to see if island will still be there -- if not, separate measurements by probe and magnetic diagnostics need to be done -- but then relation between velocity by probes and by magnetics will not be clear. Also, multiple measurements are advised as data on GOLEM are not always that reliable -- fluctuations and such. Poloidal field might be used for stabilization of plasma position, or perhaps not -- could be contraproductive. But it will need to be tried first. Not to mention that poloidal field windings are not remotedly controlled. Basically, it is more of scientific investigation with high cooperation requirements, than ordinary excercise for students, so if we will go through with this, Gomtraic participants should be properly prepared as well. Regards, Tomas 2013/4/22 R=E9fy D=E1niel > Hello guys,**** > > ** ** > > First we will have to comment the report, now the export feature of the > wiki is working, so i will do commenting of the MHD report in pdf, and se= nd > it to you for review.**** > > Second, following the proposal of Tomas, we should make a document which > describes the idea of this experiment. I am sure about that we already ha= ve > documents those describe the basic principles of both measurements, i > attached 2 files those you already know. Is there a description on the wi= ki? > **** > > What about the measurement itself? Thomas, could you please write > something about that! If application of both diagnostics simultaneously i= s > possible (i dont know how bad probes disturb the plasma) even toroidal > rotation could be resolvable from long range correltaion (?).**** > > ** ** > > cheers: Daniel**** > > ** ** > --=20 Tomas --20cf306f73d87da1a104daf1ef63 Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable
This idea to measure poloidal rotation by both probes a= nd Mirnov coils simultaneously is not something we did on GOLEM before, so = it is hard to tell how will it turn out. Currently, motivation is driven by= the fact that some aspects of rotation detected by Mirnov coils surprising= ly seem correspond to specific findings by rake probe -- namely to close-to= -constant E_r field at plasma edge regions. The arrangement will need to be= flexible. To succeed we need nice magnetic island of low m at plasma edge = (or close to it) -- i.e. low B_tor and high I_p -- have there been successf= ul rake probe measurements at such parameters? It will also take some time = to find optimal parameters, but island tailoring can be arranged relatively= easily. Also, rake probe should be inserted at the same time into plasma r= egion while island is there -- however if perturbation of plasma by probe d= oes not allow for existence of magnetic islands, two or more shots of same = parameters would be necessary -- to get usable data and to confirm that vel= ocity of rotation is reproducible.

The latter is not trivial thought -- my recent fi= ndings are that magnetic islands on GOLEM accelerate their rotation in pres= ence of external poloidal field used for control of plasma position.  = At least such are findings by magnetic diagnostics, how is it for probes is= not known to me -- we can investigate on-site. Gomtraic experiments up til= l now did not use plasma position control, but we will probably need to use= horizontally-oriented poloidal field to prevent motion of plasma during ex= periment for better interpretation of data. However, this might have some i= mpact on signal of islands -- it seemed to me that islands from when plasma= is left alone to do what it wants were more stable than those detected wit= h stabilisation winding on...

Basically, we will need 1-2 days = (depending on how machine will cooperate). First, discharge parameters will= need to be found where nice and reproducible island at plasma edge (i.e. k= nown r coordinate) is present -- as well as to identify time of its occuren= ce. Reproducible island will also enable to investigate, whether plasma rot= ation changes between shots of same parameters. Then probe can be inserted = into plasma to see if island will still be there -- if not, separate measur= ements by probe and magnetic diagnostics need to be done -- but then relati= on between velocity by probes and by magnetics will not be clear. Also, mul= tiple measurements are advised as data on GOLEM are not always that reliabl= e -- fluctuations and such. Poloidal field might be used for stabilization = of plasma position, or perhaps not -- could be contraproductive. But it wil= l need to be tried first. Not to mention that poloidal field windings are n= ot remotedly controlled.

Basically, it is more of scientif= ic investigation with high cooperation requirements, than ordinary excercis= e for students, so if we will go through with this, Gomtraic participants s= hould be properly prepared as well.

Regards,
Tom= as


2013/4/22 R=E9fy D=E1niel <refy.daniel@wigner.mta.hu>

Hello guys,

 

First we will have to comment the report, now the ex= port feature of the wiki is working, so i will do commenting of the MHD rep= ort in pdf, and send it to you for review.

Second, following the proposal of Tomas, we should make a document which de= scribes the idea of this experiment. I am sure about that we already have d= ocuments those describe the basic principles of both measurements, i attach= ed 2 files those you already know. Is there a description on the wiki?

What about the measurement itself? Thomas, could you= please write something about that! If application of both diagnostics simu= ltaneously is possible (i dont know how bad probes disturb the plasma) even= toroidal rotation could be resolvable from long range correltaion (?).<= /u>

 

cheer= s: Daniel

 

<= /div>



--
<= div>Tomas
--20cf306f73d87da1a104daf1ef63--