1. April 8-12 20031TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA First results using kinezero because faster, and also not enough time yet to check the input file maker for GS2 Kinezero: –gyrokinetic, local, eigenvalue –ion and electron, passing and trapped –electrostatic, collionless, s-  geometry, linear fast: ~150  in 1 hour on 1 CPU allows to scan extensively parameter fields C. Bourdelle, X. Garbet, G. T. Hoang et al, Nuclear Fusion 42 (2002)

2. April 8-12 20032TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA First line of attack: study impact of  in ITBs, in particular ITBs with high gradP Why  is particularly interesting? High  lowers vertical drift, therefore lowers dominant interchange instability As  is increased the confinement improves, the pressure peaks, leading to even higher  : possibility for positive feedback, like for ExB stabilization Unlike ExB stabilization, no need for external momentum input: relevant for reactor scales

3. April 8-12 20033TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA JT60-U #39056 at 6.8 s and at the barrier location, gradP is high enough to be at threshold for positive feedback between  and gradP gradP * 16! a high q (high  ) is necessary to have  below ExB but only an increase of  through gradP leads to have a complete stabilization

4. April 8-12 20034TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA Growth rates very sensitive to input profiles… Here we see that a slight change of s (from 0.4 to 0.6) leads to  higher than ExB As well for slightly lower or higher gradP (/2 or *2) would lead to lower  So it is very important to put very carefully checked profiles in the database to allow for relevent microstability analysis

5. April 8-12 20035TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA In JET ITB,  is stabilizing inside barrier A lower q would be destabilizing at barrier for ITG-TEM and ETG negligible impact of s < 0

6. April 8-12 20036TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA JET :  versus  for reversed (#53521) and monotonic (#46664) q-profiles qx2 #53521 at 6s#46664 at 6s

7. April 8-12 20037TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA  s stable unstable stable 0 ITB triggered by s < 0 ? For example, a question that would be nice to try further to answer using the ITPA database: Is it possible to sustain ITB without ExB shear, just with  stabilization? ITB triggered by high  (high q) ?

8. April 8-12 20038TTF, Madison/ 4th ITPA St Petersburg Clarisse Bourdelle Association EURATOM-CEA General remarks about the use of the ITPA profile database from C. Bourdelle I regret that the scenarios are not understandable from data in the database, for e.g. DIIID #87031 is only for 500ms, and #95989 for 600ms. Need to include scenarios in comments or with 1D data. Raw data for direct comparison experiments versus modelling (instead of comparing to already smoothed data) and a better understanding of the scenario Miss JT60-U data on the UK web site. Could not access the data despite going through recognised IP # UK site well documented. Should add any «private» tools, as Colin started to do. Colin developed an IDL tool to prepare GS2 input files. I am planning to add a tool to prepare KINEZERO input files and to convert the IDL get_profile in matlab. Different q-profiles obtained by TRANSP ( ITB database) and CRONOS particular JET #53521