ASDEX Upgrade Team

Ionita, C.

Mehlmann, F.

Müller, H. W.

Naulin, V.

Nielsen, A. H.

Rasmussen, J. J.

Rohde, V.

Schrittwieser, R.

Vianello, N.

Rasmussen, J.

Müller, H.

Nielsen, A.

MPG.PuRe

Radial transport of poloidal momentum in ASDEX Upgrade in L-mode and H-mode

Max Planck Society eDoc Server

Naulin, Volker

Juul Rasmussen, Jens

Müller, H.W.

Nielsen, Anders Henry

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 20, 2017Radial transport of poloidal momentum in ASDEX Upgrade  in L-mode and H-modeSchrittwieser, R.; Mehlmann, F.; Naulin, Volker; Rasmussen, Jens Juul; Müller, H.W.; Ionita, C.; Nielsen,Anders Henry; Vianello, N.; Rohde, V.Publication date:2012Link back to DTU OrbitCitation (APA):Schrittwieser, R., Mehlmann, F., Naulin, V., Juul Rasmussen, J., Müller, H. W., Ionita, C., ... Rohde, V. (2012).Radial transport of poloidal momentum in ASDEX Upgrade  in L-mode and H-mode. Abstract from Workshop onElectric Fields, Turbulence and Self Organization in Magnetized Plasmas (EFTSOMP 2012), Stockholm,Sweden.Radial transport of poloidal momentum in ASDEX Upgrade  in L-mode and H-mode R. Schrittwieser1, F. Mehlmann1, V. Naulin2, J.J. Rasmussen2, H.W. Müller3,  C. Ionita1, A.H. Nielsen2, N. Vianello4, V. Rohde3, ASDEX Upgrade Team3  1Inst. Ion Phys. & Appl. Physics, EURATOM-ÖAW Association, University Innsbruck, Austria 2Association EURATOM – DTU, Technical University of Denmark, Department of Physics,  DTU Risø Campus, Roskilde, Denmark 3Max-Planck-Institute for Plasma Physics, EURATOM Association, Garching, Germany 4Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova, Italy Turbulent transport and related parameters were investigated in the SOL of ASDEX Upgrade (AUG) in L-mode and H-mode discharges. The probe head [1] carries six probe pins of 1 mm diameter and 2 mm length. One pin is radially protruding by 3 mm. With this array the poloi-dal and radial electric field components Eθ,r , respectively, and the ion density n could be de-termined simultaneously. From these data in particular the radial flux of poloidal momentum, Mr = nvrvθ = 2φθ BEnE r , was derived (Bφ is the toroidal magnetic field). The density n and the radial and poloidal velocity components, vr,θ, respectively, are defined as X = X0 + Xfl (i.e. the stationary and the fluctuating components). Thereby the radial flux of poloidal momentum splits into various contributions [2,3] of which three are of interest to us: (i) Reynolds stress Re = n0vr,fl vθ,fl, (ii) convective momentum flux term vθ,0Γ = vθ,0nflvr,fl and (iii) triple fluctuat-ing term nfl vr,fl vθ,fl. Here we discuss the probability density functions (PDF) of these quanti-ties, normalized to their standard deviations, for L-mode shot #23157 during its diverted phase and H-mode shot #23163. In case of H-mode discharges, Mr is calculated separately for ELM-intervals and inter-ELM intervals, i.e., in between type-I ELMs. Whereas in H-mode due to neutral beam injection (NBI) there is an external source for toroidal angular momen-tum, in the L-mode discharge there is only intrinsic rotation. In both cases we see radial flux of poloidal momentum but with opposite signs.  References  [1]  C. Ionita, N. Vianello, H.W. Müller, et al., J. Plasma Fusion Res. Series 8, 413 (2009). [2]  F. Mehlmann, C. Ionita, V. Naulin, et al., 37th EPS Conf. Plasma Phys. (Dublin, 2010), P1.1064. [3]  J. R. Myra, D. A. Russell, D.A. D’Ippolito, Phys. Plasmas 15, 032304 (2008).  

Radial transport of poloidal momentum in ASDEX Upgrade  in L-mode and H-mode F. Mehlmann1, R. Schrittwieser1, V. Naulin2, J.J. Rasmussen2, H.W. Müller3,  C. Ionita1, A.H. Nielsen2, N. Vianello4, V. Rohde3, ASDEX Upgrade Team3  1Institute for Ion Physics and Applied Physics, EURATOM-ÖAW Association,  University of Innsbruck, Austria 2Association EURATOM – DTU, Technical University of Denmark, Department of Physics,  DTU Risø Campus, Roskilde, Denmark 3Max-Planck-Institute for Plasma Physics, EURATOM Association, Garching, Germany 4Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova, Italy Abstract: A reciprocating probe was used for localized measurements of the radial transport of poloidal momentum in the scrape-off layer (SOL) of ASDEX Upgrade (AUG). The probe measured poloidal and radial electric field components and density. We concentrate on three components of the momentum transport: Reynolds stress, convective momentum flux and tri-ple product of the fluctuating components of density, radial and poloidal electric field. For the evaluation we draw mainly on the probability density functions (PDFs).  1. Introduction The radial flux of poloidal momentum was investigated in the SOL of ASDEX Upgrade (AUG) by a probe head carrying six cold probe pins [1]. Four pins were electrically floating to derive the poloidal and radial electric field components E,r, one pin was negatively biased to determine the density n. The probe head was mounted on the midplane manipulator and in-serted during the diverted period of L-mode discharge #23157 and H-mode discharge #23163 for 100 ms in each case. The discharge parameters are summarized in Table I. Even though the reliability of this method to measure electric fields is debatable, it is yet the only one ap-plicable from the start of the probe insertion. Naturally, emissive probes would be preferable, but self-emission is no option since it takes several ms until the probes become uniformly self-emissive, if at all, which depends also on the depth of insertion (see e.g. [2]).  The radial flux of poloidal momentum reads: Mr = nvrv = 2 BEnE r  (vr, = E,r/B, B is the toroidal magnetic field). With n and the radial and poloidal velocity components, vr,, defined as X = X0 + Xfl (stationary and fluctuating component, respectively), Mr splits into various contributions [3,4]. We discuss the probability density functions (PDF) of the total momentum flux Mr and its three non-zero components: (i) Reynolds stress Re = n0vr,fl v,fl, (ii) triple fluctuating product nfl vr,fl v,fl and (iii) convective momentum v,0 = v,0nflvr,fl.  39th EPS Conference & 16th Int. Congress on Plasma Physics P2.090Table I. Plasma current Ipl, electron density ne, total magnetic field Bt, neutral beam injection power PNBI, ion cy-clotron resonance heating power PICRH, safety factor q95 and minimum distance from last closed flux surface (LCFS) for the two discharges discussed here.  Shot # Ipl (MA) ne (m–3) Bt (T) PNBI (MW) PICRH (MW) q95 lmin (mm) L-mode #23157  0,8 4,91019 –2,48   5,26 45 H-mode #23163  0,8 6,71019 –2,48 5,1 3,7 5,25 38 The statistical spread of the data was usually very strong. Therefore it is problematic to obtain rea-sonable values for the higher statistical moments (skewness and kurtosis). Deriving a PDF means di-viding the data series into cells and counting the hits in each cell. However, in the wings of the distribution only few points are left. So the statistics of big num-bers cannot be applied any more. To overcome this problem a rule was defined: When 5 neighbouring cells have less than 5 hits, these cells are ignored. The hits in the cells and thereby the limits can be varied more or less arbitrarily by varying the cell size. To avoid arbitrariness as far as possible, we have chosen a constant cell size of 0,1FWHM (Full Width Half Maximum) of the distributions. The PDFs are normalized to the standard deviations (stdev). These very complex questions will be treated in a forthcoming long paper [5].  2. Experimental results and discussion Fig. 1 shows the PDFs of the total transport of momentum Mr and of the three above men-tioned components for L-mode discharge #23157. Table II contains mean values, standard deviations, skewnesses and kurtoses of the data series.  In case of H-mode discharge #23163 (see Fig. 2), Mr and its three com-ponents were also calculated separately for ELM-intervals and inter-ELM inter-vals, i.e. all ELM intervals and all inter-ELM intervals were concatenated sepa-rately. Fig. 2(a) shows the PDFs for the entire H-mode, (b) for the inter-ELM in-Fig. 1: PDFs of the total momentum transportMr (black line), and of the three components during the diverted L-mode discharge #23157: Reynolds stress Re (olive line), triplefluctuating product nfl vr,fl v,fl (red line), con-vective momentum flux v,0 (blue line). in-sertion time interval t = 2,195-2,295 s.  -5 -4 -3 -2 -1 0 1 2 3 4 50,010,11L-mode #23157  Mr Re v,flvr,flnfl v,0PDF(Mr)*stdev(Mr) (m-1s-2 )Mr/stdev(Mr)Table II: Mean values, standard deviation (stdev), skew-ness and kurtosis of the total flux of momentum Mr and its three components Reynolds stress Re, triple fluctuating product nfl vr,fl v,fl and convective momentum v,0 = v,0nflvr,fl for L-mode discharge #23157. L-mode #23157 Mean value Stdev Skew-ness Kurto-sis Mr 7,271020 20,731021 3,37 42,14Re -9,021020 9,251021 -0,85 20,90nfl vr,fl v,fl  2,911020 6,871021 2,99 73,49v,0  13,011020 12,611021 3,50 34,7139th EPS Conference & 16th Int. Congress on Plasma Physics P2.090tervals and (c) for the ELM intervals. Table III indicates the corresponding mean values, stan-dard deviations, skewnesses and kurtoses of the data series.  Fig. 1 of the L-mode discharge shows rather symmetric PDFs with that of the Reynolds stress showing the highest symmetry, a negative mean value and a slightly negative skewness. All other PDFs show positive skewness.  The PDFs of the entire H-mode discharge (Fig. 2(a)) show a similar behaviour. Also in this case the Reynolds stress shows the most sym-metric distribution, with low, however positive val-ues of mean and skewness. The PDFs of the other three components are strongly positively skewed for values of Mr/stdev(Mr) > 2. This is also reflected in their skewness values (Table III(a)). The PDFs of Fig. 2(b) (inter-ELM intervals) are all relatively symmetric with that of the convective term most bulging, i.e. most positively skewed in the range of Fig. 2. PDFs of the total momentum transport Mr (black line) and of the three components for H-mode discharge #23163, for the entire H-mode (a), during the inter-ELM intervals (b) and during the ELM intervals (c): Reynolds stress Re (green line), triple fluctuating productnfl vr,fl v,fl (red line), convective momentumflux v,0 (blue line), t = 2,970-3,070 s.  -5 -4 -3 -2 -1 0 1 2 3 4 50,010,11H-mode #23163Entire time interval Mr Re v,flvr,flnfl v,0PDF(Mr)*stdev(Mr) (m-1s-2 )Mr/stdev(Mr)(a)-5 -4 -3 -2 -1 0 1 2 3 4 50,010,11H-mode #23163inter ELM inter-vals only Mr Re v,flvr,flnfl v,0PDF(Mr)*stdev(Mr) (m-1s-2 )Mr/stdev(Mr)(b)-5 -4 -3 -2 -1 0 1 2 3 4 50,010,11PDF(Mr)*stdev(Mr) (m-1s-2 )Mr/stdev(Mr) Mr Re v,flvr,flnfl v,0H-mode #23163ELMs only(c)Table III: Mean values, standard deviation (stdev), skewness and kurtosis of the total flux of momentum Mr and its three components Reynolds stress Re, triple fluctuating product nfl vr,fl v,fl and convective momentum v,0 = v,0nflvr,fl for the entire H-mode discharge #23163 (a), for the concatenated in-ter-ELM intervals (b) and the concatenated ELM intervals (c).  (a) Entire H-mode  Mean value Stdev Skewness Kurtosis Mr 1,12.1023 11,361023 8,31 107,41Re 0,161023 3,781023 3,56 56,57nfl vr,fl v,fl  0,331023 4,791023 7,71 111,99v,0  0,681023 4,451023 9,01 106,05(b) Inter-ELMs    Mr 13,761021 2,011023 0,81 38,04Re -2,111021 1,661023 -0,18 14,51nfl vr,fl v,fl  -0,391021 0,641023 0,14 44,47v,0  16,621021 0,861023 2,02 32,91(c) ELMs    Mr 8,521023 3,081024 2,62 10,33Re 1,431023 0,971024 1,33 7,24nfl vr,fl v,fl  2,771023 1,341024 2,35 10,56v,0  4,381023 1,181024 2,93 10,4739th EPS Conference & 16th Int. Congress on Plasma Physics P2.090Mr/stdev(Mr)  1 – 2 (see also Table III(b)). Thus between ELMs the mo-mentum transport appears to be domi-nated mainly by convection. Expect-edly during ELMs (Fig. 2(c)) we find the most strongly skewed PDFs for Mr and all three of its components, corre-sponding to the relatively large skew-nesses in Table III(c). However, most of the transport occurs in the range of Mr/stdev(Mr) > 1 which does not con-tribute so much to the skewness mo-mentum. A more comprehensive treatment of these effects will be presented in [5].  As a descriptive example, Fig. 3 shows the temporal evolution of the PDF of the total radial transport of poloidal momentum Mr (absolute values) during the entire insertion of the probe head in case of H-mode shot #23163. The colour code shows increasing relative ampli-tude from violet to red from 610–3 to 1. The ELMs are recognizable by their much broader PDFs and are marked by red arrows.  Eventually we point out that in H-mode, due to the NBI, there is an external source for toroidal angular momentum. However, in an ohmic L-mode discharge there can only be in-trinsic rotation, in which case the momentum should basically be generated from turbulence in the form of residual stresses (asymmetry flows) by the Reynolds stress and direct interac-tion with the SOL flows.  Acknowledgements This work, supported by the European Communities under the Contracts of Associations between EURATOM and ÖAW, IPP, ENEA-RFX and DTU, was carried out within the framework of the EFDA. The content of the publication is the sole responsibility of its authors and it does not necessarily represent the views of the Commis-sion or its services. This work was also supported by grant P19901 of the Austrian Science Fund (FWF). References [1]  C. Ionita, N. Vianello, H.W. Müller, et al., J. Plasma Fusion Res. Series 8, 413 (2009). [2]  B. Nold, T.T. Ribeiro, M. Ramisch, et al., New J. Phys. (2012), accepted. [3]  F. Mehlmann, C. Ionita, V. Naulin, et al., 37th EPS Conf. Plasma Phys. (Dublin, 2010), P1.1064. [4]  J. R. Myra, D. A. Russell, D.A. D’Ippolito, Phys. Plasmas 15, 032304 (2008).  [5]  F. Mehlmann, V. Naulin, C. Ionita, et al., in preparation.  Fig. 3. Temporal evolution of the PDF of the absolute values of the total radial transport Mr of poloidal momentum during H-mode shot #23163.  39th EPS Conference & 16th Int. Congress on Plasma Physics P2.090

English

A reciprocating probe was used for localized measurements of the radial transport of poloidal momentum in the scrape-off layer (SOL) of ASDEX Upgrade (AUG). The probe measured poloidal and radial electric field components and density. We concentrate on three components of the momentum transport: Reynolds stress, convective momentum flux and triple product of the fluctuating components of density, radial and poloidal electric field. For the evaluation we draw mainly on the probability density functions (PDFs)

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Downloaded from orbit.dtu.dk on: Dec 20, 2017Radial transport of poloidal momentum in ASDEX Upgrade in L-mode and H-modeMehlmann, F.; Schrittwieser, R.; Naulin, Volker; Rasmussen, Jens Juul; Müller, H.W.; Ionita, C.; Nielsen,Anders Henry; Vianello, N.; Rohde, V.Published in:Proceedings of the 39th EPS Conference on Plasma Physics and 16th International Congress on PlasmaPhysicsPublication date:2012Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Mehlmann, F., Schrittwieser, R., Naulin, V., Juul Rasmussen, J., Müller, H. W., Ionita, C., ... Rohde, V. (2012).Radial transport of poloidal momentum in ASDEX Upgrade in L-mode and H-mode. In Proceedings of the 39thEPS Conference on Plasma Physics and 16th International Congress on Plasma Physics (pp. P2.090)Radial transport of poloidal momentum in ASDEX Upgrade  in L-mode and H-mode F. Mehlmann1, R. Schrittwieser1, V. Naulin2, J.J. Rasmussen2, H.W. Müller3,  C. Ionita1, A.H. Nielsen2, N. Vianello4, V. Rohde3, ASDEX Upgrade Team3  1Institute for Ion Physics and Applied Physics, EURATOM-ÖAW Association,  University of Innsbruck, Austria 2Association EURATOM – DTU, Technical University of Denmark, Department of Physics,  DTU Risø Campus, Roskilde, Denmark 3Max-Planck-Institute for Plasma Physics, EURATOM Association, Garching, Germany 4Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Padova, Italy Abstract: A reciprocating probe was used for localized measurements of the radial transport of poloidal momentum in the scrape-off layer (SOL) of ASDEX Upgrade (AUG). The probe measured poloidal and radial electric field components and density. We concentrate on three components of the momentum transport: Reynolds stress, convective momentum flux and tri-ple product of the fluctuating components of density, radial and poloidal electric field. For the evaluation we draw mainly on the probability density functions (PDFs).  1. Introduction The radial flux of poloidal momentum was investigated in the SOL of ASDEX Upgrade (AUG) by a probe head carrying six cold probe pins [1]. Four pins were electrically floating to derive the poloidal and radial electric field components E,r, one pin was negatively biased to determine the density n. The probe head was mounted on the midplane manipulator and in-serted during the diverted period of L-mode discharge #23157 and H-mode discharge #23163 for 100 ms in each case. The discharge parameters are summarized in Table I. Even though the reliability of this method to measure electric fields is debatable, it is yet the only one ap-plicable from the start of the probe insertion. Naturally, emissive probes would be preferable, but self-emission is no option since it takes several ms until the probes become uniformly self-emissive, if at all, which depends also on the depth of insertion (see e.g. [2]).  The radial flux of poloidal momentum reads: Mr = nvrv = 2 BEnE r  (vr, = E,r/B, B is the toroidal magnetic field). With n and the radial and poloidal velocity components, vr,, defined as X = X0 + Xfl (stationary and fluctuating component, respectively), Mr splits into various contributions [3,4]. We discuss the probability density functions (PDF) of the total momentum flux Mr and its three non-zero components: (i) Reynolds stress Re = n0vr,fl v,fl, (ii) triple fluctuating product nfl vr,fl v,fl and (iii) convective momentum v,0 = v,0nflvr,fl.  39th EPS Conference & 16th Int. Congress on Plasma Physics P2.090Table I. Plasma current Ipl, electron density ne, total magnetic field Bt, neutral beam injection power PNBI, ion cy-clotron resonance heating power PICRH, safety factor q95 and minimum distance from last closed flux surface (LCFS) for the two discharges discussed here.  Shot # Ipl (MA) ne (m–3) Bt (T) PNBI (MW) PICRH (MW) q95 lmin (mm) L-mode #23157  0,8 4,91019 –2,48   5,26 45 H-mode #23163  0,8 6,71019 –2,48 5,1 3,7 5,25 38 The statistical spread of the data was usually very strong. Therefore it is problematic to obtain rea-sonable values for the higher statistical moments (skewness and kurtosis). Deriving a PDF means di-viding the data series into cells and counting the hits in each cell. However, in the wings of the distribution only few points are left. So the statistics of big num-bers cannot be applied any more. To overcome this problem a rule was defined: When 5 neighbouring cells have less than 5 hits, these cells are ignored. The hits in the cells and thereby the limits can be varied more or less arbitrarily by varying the cell size. To avoid arbitrariness as far as possible, we have chosen a constant cell size of 0,1FWHM (Full Width Half Maximum) of the distributions. The PDFs are normalized to the standard deviations (stdev). These very complex questions will be treated in a forthcoming long paper [5].  2. Experimental results and discussion Fig. 1 shows the PDFs of the total transport of momentum Mr and of the three above men-tioned components for L-mode discharge #23157. Table II contains mean values, standard deviations, skewnesses and kurtoses of the data series.  In case of H-mode discharge #23163 (see Fig. 2), Mr and its three com-ponents were also calculated separately for ELM-intervals and inter-ELM inter-vals, i.e. all ELM intervals and all inter-ELM intervals were concatenated sepa-rately. Fig. 2(a) shows the PDFs for the entire H-mode, (b) for the inter-ELM in-Fig. 1: PDFs of the total momentum transportMr (black line), and of the three components during the diverted L-mode discharge #23157: Reynolds stress Re (olive line), triplefluctuating product nfl vr,fl v,fl (red line), con-vective momentum flux v,0 (blue line). in-sertion time interval t = 2,195-2,295 s.  -5 -4 -3 -2 -1 0 1 2 3 4 50,010,11L-mode #23157  Mr Re v,flvr,flnfl v,0PDF(Mr)*stdev(Mr) (m-1s-2)Mr/stdev(Mr)Table II: Mean values, standard deviation (stdev), skew-ness and kurtosis of the total flux of momentum Mr and its three components Reynolds stress Re, triple fluctuating product nfl vr,fl v,fl and convective momentum v,0 = v,0nflvr,fl for L-mode discharge #23157. L-mode #23157 Mean value Stdev Skew-ness Kurto-sis Mr 7,271020 20,731021 3,37 42,14Re -9,021020 9,251021 -0,85 20,90nfl vr,fl v,fl  2,911020 6,871021 2,99 73,49v,0  13,011020 12,611021 3,50 34,7139th EPS Conference & 16th Int. Congress on Plasma Physics P2.090tervals and (c) for the ELM intervals. Table III indicates the corresponding mean values, stan-dard deviations, skewnesses and kurtoses of the data series.  Fig. 1 of the L-mode discharge shows rather symmetric PDFs with that of the Reynolds stress showing the highest symmetry, a negative mean value and a slightly negative skewness. All other PDFs show positive skewness.  The PDFs of the entire H-mode discharge (Fig. 2(a)) show a similar behaviour. Also in this case the Reynolds stress shows the most sym-metric distribution, with low, however positive val-ues of mean and skewness. The PDFs of the other three components are strongly positively skewed for values of Mr/stdev(Mr) > 2. This is also reflected in their skewness values (Table III(a)). The PDFs of Fig. 2(b) (inter-ELM intervals) are all relatively symmetric with that of the convective term most bulging, i.e. most positively skewed in the range of Fig. 2. PDFs of the total momentum transport Mr (black line) and of the three components for H-mode discharge #23163, for the entire H-mode (a), during the inter-ELM intervals (b) and during the ELM intervals (c): Reynolds stress Re (green line), triple fluctuating productnfl vr,fl v,fl (red line), convective momentumflux v,0 (blue line), t = 2,970-3,070 s.  -5 -4 -3 -2 -1 0 1 2 3 4 50,010,11H-mode #23163Entire time interval Mr Re v,flvr,flnfl v,0PDF(Mr)*stdev(Mr) (m-1s-2)Mr/stdev(Mr)(a)-5 -4 -3 -2 -1 0 1 2 3 4 50,010,11H-mode #23163inter ELM inter-vals only Mr Re v,flvr,flnfl v,0PDF(Mr)*stdev(Mr) (m-1s-2)Mr/stdev(Mr)(b)-5 -4 -3 -2 -1 0 1 2 3 4 50,010,11PDF(Mr)*stdev(Mr) (m-1s-2)Mr/stdev(Mr) Mr Re v,flvr,flnfl v,0H-mode #23163ELMs only(c)Table III: Mean values, standard deviation (stdev), skewness and kurtosis of the total flux of momentum Mr and its three components Reynolds stress Re, triple fluctuating product nfl vr,fl v,fl and convective momentum v,0 = v,0nflvr,fl for the entire H-mode discharge #23163 (a), for the concatenated in-ter-ELM intervals (b) and the concatenated ELM intervals (c).  (a) Entire H-mode  Mean value Stdev Skewness Kurtosis Mr 1,12.1023 11,361023 8,31 107,41Re 0,161023 3,781023 3,56 56,57nfl vr,fl v,fl  0,331023 4,791023 7,71 111,99v,0  0,681023 4,451023 9,01 106,05(b) Inter-ELMs    Mr 13,761021 2,011023 0,81 38,04Re -2,111021 1,661023 -0,18 14,51nfl vr,fl v,fl  -0,391021 0,641023 0,14 44,47v,0  16,621021 0,861023 2,02 32,91(c) ELMs    Mr 8,521023 3,081024 2,62 10,33Re 1,431023 0,971024 1,33 7,24nfl vr,fl v,fl  2,771023 1,341024 2,35 10,56v,0  4,381023 1,181024 2,93 10,4739th EPS Conference & 16th Int. Congress on Plasma Physics P2.090Mr/stdev(Mr)  1 – 2 (see also Table III(b)). Thus between ELMs the mo-mentum transport appears to be domi-nated mainly by convection. Expect-edly during ELMs (Fig. 2(c)) we find the most strongly skewed PDFs for Mr and all three of its components, corre-sponding to the relatively large skew-nesses in Table III(c). However, most of the transport occurs in the range of Mr/stdev(Mr) > 1 which does not con-tribute so much to the skewness mo-mentum. A more comprehensive treatment of these effects will be presented in [5].  As a descriptive example, Fig. 3 shows the temporal evolution of the PDF of the total radial transport of poloidal momentum Mr (absolute values) during the entire insertion of the probe head in case of H-mode shot #23163. The colour code shows increasing relative ampli-tude from violet to red from 610–3 to 1. The ELMs are recognizable by their much broader PDFs and are marked by red arrows.  Eventually we point out that in H-mode, due to the NBI, there is an external source for toroidal angular momentum. However, in an ohmic L-mode discharge there can only be in-trinsic rotation, in which case the momentum should basically be generated from turbulence in the form of residual stresses (asymmetry flows) by the Reynolds stress and direct interac-tion with the SOL flows.  Acknowledgements This work, supported by the European Communities under the Contracts of Associations between EURATOM and ÖAW, IPP, ENEA-RFX and DTU, was carried out within the framework of the EFDA. The content of the publication is the sole responsibility of its authors and it does not necessarily represent the views of the Commis-sion or its services. This work was also supported by grant P19901 of the Austrian Science Fund (FWF). References [1]  C. Ionita, N. Vianello, H.W. Müller, et al., J. Plasma Fusion Res. Series 8, 413 (2009). [2]  B. Nold, T.T. Ribeiro, M. Ramisch, et al., New J. Phys. (2012), accepted. [3]  F. Mehlmann, C. Ionita, V. Naulin, et al., 37th EPS Conf. Plasma Phys. (Dublin, 2010), P1.1064. [4]  J. R. Myra, D. A. Russell, D.A. D’Ippolito, Phys. Plasmas 15, 032304 (2008).  [5]  F. Mehlmann, V. Naulin, C. Ionita, et al., in preparation.  Fig. 3. Temporal evolution of the PDF of the absolute values of the total radial transport Mr of poloidal momentum during H-mode shot #23163.  39th EPS Conference & 16th Int. Congress on Plasma Physics P2.090

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Radial transport of poloidal momentum in ASDEX Upgrade in L-mode and H-mode

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