Transcript Status and plans for the LH transition database

L-H threshold database:
Status and Plans
J.W. Hughes, J. Stillerman, MIT PSFC
Y. Martin, CRPP-EPFL
P. Gohil, GA
D. McDonald, JET-EFDA
Meeting of the ITPA Pedestal and Transport & Confinement
Topical Groups
Princeton, NJ
6 October 2009
L-H threshold database is changing hands,
expanding
• MIT is preparing to administer the L-H threshold database
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Server operational and ready for import of existing database
Y. Martin is ready to export
Supported by PSFC computing personnel
Accessible to ITPA participants
Community usage, openness encouraged
• Reduced role of centralized administration
• Simple password authentication for ease of access (server will be outside
facility firewall)
• Development of APIs to allow ease of data extraction, insertion for individual
users
– Nightly backups (kept inside firewall) plus version archiving following
publications
• Two stage development
– Existing scalar power threshold database, on an SQL server
– Profile data, stored in standardized MDSplus tree structures (analogous
to existing profile databases used by Pedestal, DIV/SOL groups)
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How we got here
• Transfer first discussed at
10/08 ITPA meeting
• At same meeting, L-H
transition working group
was formed, with contacts at
many facilities
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AUG: F. Ryter
C-Mod: J. Hughes
DIII-D: P. Gohil
JET: Y. Andrews/D. McDonald
JT-60U: K. Kamiya
MAST: H. Meyer/M. Valovic
NSTX: R. Maingi
TCV: Y. Martin
• Generally agreed that a
profile database would
provide greater physics
content for transition studies
– Continued discussions among
working group members
attending spring T&C meeting
– General discussion session at
the spring pedestal meeting
• This meeting: Agree on
purpose, form of profile
database
– Input from both
experimentalists and modelers
is desired
– TUMAN-3M: S. Lebedev
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A goal-oriented threshold DB
• DB effort will only be effective if clear goals are
established, e.g.:
• Profile data for reducing the uncertainty in Pthresh
prediction
– Eliminate the “black magic” of hidden variables
– In individual devices: Identification of important local parameters
as part of global parameter scans
– Common threshold conditions across devices with joint
experiments defined
• Profile data for model testing
– A potential repository for well-diagnosed discharges
– Profile evolution before and across the L-H transition
– Turbulence characteristics?
• Profile data for predictive capabilites (ITER)
– Short term: 0D (and some 1D?) approach based on JEX results
– Long term: simulations based on validated models
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Ideas for profile database development
• Participants in database effort determine
composition of profile DB
• Content driven by priorities, key goals of
researchers (see previous slide)
• Data sets should be sufficient to provide useful
profiles, but not so extensive as to discourage
participation
• A possible model is a tiered data set
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Tier 1. Global parameters: <ne>, BT, IP, etc. (plus d/dt of each)
Tier 2. Essential profiles: ne,i, Te,i, vif, viq et al.
Tier 3. Profiles requiring analysis: Poh, Paux, jBS et al.
Tier 4. Advanced profile measurements: Prad, n0, flucts. et al.
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How to proceed
• The pedestal profile database is an excellent starting
point
– Motivation for its development was similar
– Much of the work has already been done
– Can be merged with existing L-H db parameters
• Compelling features
– Provides a uniform data structure built on MDSplus trees
– Upwards compatible with the (core) confinement profile DB
– Contains branches for data of varied sophistication: .ZEROD:,
.ONED:, .TWOD:, .ONEDTR:, .TWODTR:, etc.
– Contains mechanism for timing with respect to plasma events
(e.g. L-H transition time, H-L transition time, sawteeth)
– .DIV branch provides inputs for SOL/divertor modeling
• Downside: Trees don’t populate themselves. Work is
required of contributors.
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Suggested plan of attack
• Build on existing nodes of confinement and
pedestal profile trees
• Identify additional measurements which
should be included (discussion among
interested parties to follow)
• Identify a suitable joint experiment to
motivate initial deposits into the DB
• Use DB to facilitate analysis/modeling for
ITER research, publications
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Discussion
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Discussion
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Discussion
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