PAC 2003

Jim IrbyMIT-PSFC

PAC Meeting 02/20-02/21 2003

Outline

• Status– Operations– Diagnostics– Data system

• Five Year Plan– Machine– Diagnostics– Data system

• Short Term Plans

PAC Meeting 02/20-02/21 2003

StatusOperations

• Alcator C-Mod operated from 6/7/2002 to 11/12/2002 after the successful inspection of the TF magnet and other major machine components

• During the last run campaign:– Approximately 800 plasma discharges with a startup

reliability of 75% were produced– Startup reliability during the month of October was

85% with several days >95%.– We maintained about 32 shots/day

• By September 30th we had performed 31.5 physics run days out of a proposed 32

PAC Meeting 02/20-02/21 2003

Operations• Milestone 79: inner divertor installation completed on time

on 3/8/2002 – Ip at new record level of 1.67 MA (7.8 T) for C-Mod– More freedom in plasma shape control

Lower δ = 0.73

PAC Meeting 02/20-02/21 2003

Operations

• We continue to improve power handling capability of the ICRF antennas and make upgrades to the control/protection/data acquisition systems– 1.5 MW pulses for 4 s into GA dummy load

• Improvements to cryostat were made– Horizontal port inner seals now outside cryostat where

they can be kept warm– Horizontal ports are removable with igloo in place– Higher magnet cooling rate: 50% increase in number of

discharges per day• Improved tangential access: Mods to cryostat and cylinder

PAC Meeting 02/20-02/21 2003

Changes to Cylinder and Cryostat

Add flat section to cylinderfor tangential access

Instrumentation ports

Openings around portsincreased in size

PAC Meeting 02/20-02/21 2003

Operations: Lower Hybrid Project

• LH HVPS and crowbar have been brought into operation– 50 kV, 208 A supply– Solid state crowbar with < 10 �s time response

• Water cooling system acceptance tests completed– 600 and 1200 gallons/min pumps at 100 psi

• Phase and amplitude control system for klystrons now a major activity

• PPPL is maintaining a 3/31/2003 delivery date for the LH launcher

PAC Meeting 02/20-02/21 2003

Shroud heaters

Port andrails

CouplerBack end

CouplerFront endTaper

RFProbe Grill

Drive

PAC Meeting 02/20-02/21 2003

Operations

• Control coils have been fabricated and driven to full current (control locked modes)

• First of at least two TMX power supplies is operational ---control, data acquisition, protection (300 V, 3000 A)

• Installation of coils proceeding on igloo

PAC Meeting 02/20-02/21 2003

Operations : Preparations for new cryopump1021002021 EFIT: 1.000

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• Plasma geometry has been varied from lower single null to upper single null

• Pressures at the top and bottom of the vessel have been measured ---upper vessel pressure varied from 0.1 to 10 mTorr

• Baffles will be added to restrict gas flow at top of vesselR (m)R (m)

Z (m

)

Z (m

)

PAC Meeting 02/20-02/21 2003

Diagnostics

• New inner divertor diagnostics are operational and providing important information for reactor design

• Core TS system greatly improved with new polychromator installations (GA polychromator design)

• High speed cameras used to image turbulence at the edge and to follow Li pellet ablation trails (current profiles)

• Inner wall scanning probe used to measure density, temperature, and fluctuation profiles for comparison with outer probes

PAC Meeting 02/20-02/21 2003

Diagnostics

• Number of invessel viewing cameras increased– Improved our ability to correlate machine problems

with activity in vessel• Several new Penning gauges measure pressure under outer

divertor modules and in main chamber– New capillary lines with calibrated flow rates allow gas

to be injected around the vessel to measure resulting pressures and conductances with and w/o plasma

Sawtoothing

MSE q profile

ne=1.2×1020OhmicH.Yuh – Feb 20 2003 C-Mod PAC

MSE Data Scatter is acceptable

Edge Hα (30% higher in L)Viewing GeometryLow Edge Density

Beam PenetrationBeam CurrentITB/Core Density in H-mode 2.220 =n

2.220 =n 3.220 =n

AI Beam 0.4= AI Beam 4.3= AI Beam 5.3=

1

2

.120 =n

.120 =n

3.120 =n

AI Beam 2.4= AI Beam 1.4= AI Beam 3.4=

H.Yuh – Feb 20 2003 C-Mod PAC

PAC Meeting 02/20-02/21 2003

Data System

• Data system currently deals effectively with over 500 MB of data per discharge

• Highly distributed network of servers and workstations has allowed incremental upgrades to match demand

• We continue to move away from DEC/VMS based systems– 12 linux workstations now fully integrated into between

shot data analysis– 36 node (linux) Beowulf cluster developed and used for

between shot analysis and large codes

PAC Meeting 02/20-02/21 2003

Data System

• A second linux server with a 1.5 Tbyte RAID system will soon replace our VMS based data acquisition server

• Tbyte scale RAID magnetic disks --- ALL C-Mod data is online and accessible within a few ms

• Magnetic tape backup system upgraded to accommodate the dramatic increase in data rate

PAC Meeting 02/20-02/21 2003

Data System

• We continue the transition away from CAMAC to CPCIbased hardware– CPCI crates include diskless linux based computers

capable of sub-sampling and preliminary data analysis– Magnetics data acquisition completely replaced during

last run campaign --- better data rates with higher resolution --- Higher reliability

– LH systems will come online as CPCI system– ICRF data acquisition migrating to CPCI

PAC Meeting 02/20-02/21 2003

Five Year Plan

PAC Meeting 02/20-02/21 2003

Machine

• Upgrades will be performed and new systems installed to– Bring lower hybrid project into operation– Allow reliable, high power density, long pulse

operation with density control (divertor, cryopump)– Improve reliability and power handling capability of the

ICRF systems• Plasma control systems will be improved

– Control coils– Power supplies– Digital PCS

• New klystrons will be purchased and old klystrons repaired to ensure replacements will be available

PAC Meeting 02/20-02/21 2003

Machine

FY08Tungsten Brush?Advanced Divertor Prototype (BPX)

FY05Install coils for locked mode control(inside cryostat)

Control Coils

FY05Improved load tolerant designFree port space for diagnostics

2nd ICRF 4-Strap Antenna

FY05Prepare for long pulse, high power operation

ICRF Faraday ScreenUpgrades

FY04FY05

High heat load capability (25 MW/m2)Reactor relevant

Tungsten Brush Tilesand Test Module

FY06Improve heat load capabilityStrengthen

Lower Outer Divertor

FY05Gain density control during H-modeDensity/Impurity control during AT

Cryopump

PAC Meeting 02/20-02/21 2003

Machine

FY04Allow transmitters to see matched load during large changes in plasma loadingInvestigating wg and stripline designs

Fast Ferrite TunerPrototype

FY05Improvements made to EFC and EF2Better plasma control during high performance operation

Power Supply Upgrades

BeginsFY04

Digital system will allow more control lines and much improved control algorithms --- real-time EFIT

Plasma Control System Upgrade

FY05Reduce power density at antenna grill Second LH Launcher

FY05Increase LH source power from 3 to 4 MW

LH Source Power Upgrade

PAC Meeting 02/20-02/21 2003

Cryopump (FY05)– Control density and possibly

reduce impurities during H-mode and AT operation

– Pumping speeds approximately 25k-l/s

– Toroidal LHe filled tube surrounded by LN2 heat shield

– New upper chamber armor protects pump

– Gas flows out between gussets to the pump --- baffle increases pressure in upper chamber

– Preliminary design phase– Loss of diagnostic access

PAC Meeting 02/20-02/21 2003

Lower Outer Divertor (FY05)– Current outer divertor is at heat

load design limits– A new divertor will be required

for long pulse AT operation at auxiliary power levels approaching 10 MW

– New divertor will have a simple cylindrical shape that will be easy to fabricate

– Toroidally continuous vertical plate (no leading edges) ---some loss of diagnostic access

– One module will be of the advanced tile design

PAC Meeting 02/20-02/21 2003

Diagnostics Plans

• New diagnostics are planned for the next grant period to increase our capability– Several new diagnostics will focus on improved

understanding of ITB discharges --- better core profile and rotation information for example

– Others are coming online to help diagnose the operation of the new lower hybrid system

– We will continue to improve diagnostics for the SOL, edge plasma, and turbulence and fluctuations

• Loss of diagnostic access as the lower hybrid system is installed will require installation of new horizontal ports

PAC Meeting 02/20-02/21 2003

Diagnostics

FY04FY05FY07

New 2D CCD detector for current systemImpurity density spectrometer: He3 minoritySpectrometer with new views and better background measurements

CXRS Upgrade

FY04FY05

Double number of radial measurementsSecond view (discriminate E vs V X B)

MSE Upgrade

FY05Replace beam on loan from RFX with even better performance device, 55 kV, 8 amps source, .06 m 1/e, 1.5 s, 70% full energy current fraction in source , Delivery time 14-15 months (start procurement soon)

Long Pulse DNB

PAC Meeting 02/20-02/21 2003

Diagnostics

FY05Confirmation and support of MSEOperate at high density, high temperatureUp to 30 poloidally viewing chords, � > 10 �m

PolarimeterInterferometer

FY06

FY07

FY07

Increased number of channels and improved data acq for better spatial, temporal, and k-space resolutionA second PCI system will be added at another toroidal location: extent of wave prop and mode conversionCrossed beams: 2D imaging of ETG turbulence and mode converted ICRF/IBW waves

PCI

FY04Measure profile and energy spectrum of suprathermal electrons during LH Exp32 channels, 20-200 keV

Hard X-Ray Camera

PAC Meeting 02/20-02/21 2003

Diagnostics

FY06New view to gain information about non-thermal spectrum. Diagnose LH coupling physics and deposition profile

Non Thermal ECE

FY07New radiometers will be added to extend both low and high frequency range: low and high magnetic field accessibility

Heterodyne ECE

FY04Six new channels will be added to improve coverage of the plasma core; particularly important for ITB discharges

Core Thomson Scattering

FY04Allow control of drive phaseActive MHD Antennas

PAC Meeting 02/20-02/21 2003

Diagnostics

FY05Doubly bent crystal and 2D solid state detectorRotation velocity and Ti over most of plasma cross section w/o shot-to-shot scanning

Imaging X-Ray Crystal Spectrometer

FY06High resolution, high throughput grating following design of Chandra X-Ray telescopeMeasure bulk rotation in outer half of plasma

High Resolution Transmission Grating VUV

FY06Improve toroidal resolution; low- to intermediate-n

Inboard Mirnov Coil Upgrade

FY06Study both long and short wavelength fluctuations in large gradient regions (transport region)

Laser Scattering(possibly CO2)

PAC Meeting 02/20-02/21 2003

Diagnostics

FY05Measure bulk flow in plasma edge/SOLDoppler shifts and broadening of emission lines using high resolution visible spectrometer with 2D multi-element detector

SOL Flow Imaging

FY05andFY07

Measure divertor temperatures during high auxiliary power and long pulse dischargesEssential to monitor operation of divertor components

Divertor IR Cameras

FY06Measure ICRF generated hydrogen tail by observing neutrals created by charge exchange with DNB

Active CX NPA

FY05Extend edge TS out to the limiterMeasure temperature and density where typically only probes have been used with limited number of temporal points

SOL Thomson Scattering

PAC Meeting 02/20-02/21 2003

Diagnostics

FY07Investigate pedestal profiles and fluctuationsHigh Resolution Edge ECE System

FY04to FY06

Microbalances will be placed around vessel to measure deposition

Material Deposition Monitors

FY04Measure density profile near surface of the LH grill. Critical to understanding of coupling of LH power --- line ratio, probes?

LH Grill Density Diagnostic

FY052D (radial, poloidal) patterns of density and temperature in outboard SOLFiber based system using ultra-high-speed-movie camera

Edge Fluctuation Imaging

PAC Meeting 02/20-02/21 2003

Diagnostics

FY06Determine if dust plays a significant role in particle fueling and radiation in the SOL

Mie Scattering of Dust in the SOL

FY06Measure 2D neutral density profiles at the plasma edgeMultiple Lyman-� arrays

Spectral Tomography of Neutrals

FY04High resolution measurement of poloidal magnetic field at the edgeMeasure intensity ratios of Li-multiplet lines produced by 50kV Li atomic beam

Li Beam Edge Polarimeter

FY06Measure profiles of ni, Ti, and �ni in the pedestal

LIF Fluctuation Mapping at the Edge

PAC Meeting 02/20-02/21 2003

Diagnostics

FY07Upgrade of detector for impurity source survey spectrometer

2D CCD Detector

FY06andFY08

Provide cameras at MIT to replace camera on loan from PPPL --- turbulence, tranport

Ultra High Speed Framing Cameras

FY05Study probe perturbation effects on transportDouble the number of signals/probe

New A-Port Scanning ProbeDrive

FY05Measure density, temperature, and potential fluctuations at high bandwidth using the three scanning probesAdd 50 MHz sampling rate cPCI data acq

Upgrade to Probe Bias Electronics

PAC Meeting 02/20-02/21 2003

Data System

• Major task over the next few months will be to complete the transition from the VMS to the linux computing environment (est CY2004)

• Linux configuration by the end of 2004– 35 desktop systems– 3 to 4 servers

• Local area network will be upgraded to take full advantage of the i/o rates of the new systems– Gbps links to each desktop– 10 Gbps backbone

PAC Meeting 02/20-02/21 2003

Data System

• Mass storage requirements will be met with large magnetic disk storage arrays– Current data rates require 1 to 2 Tbytes of new capacity

per year– New tape systems will also be required

• The replacement of CAMAC with CPCI digitizers, timing, and waveform modules will continue– Coordination with other major US and international

facilities is important and ongoing• Improvements will be made to video data acquisition

systems

PAC Meeting 02/20-02/21 2003

Short Term Plans

• Pumpdown in early March 2003• Flywheel inspection mid March to early April 2003• LH launcher arrives end March 2003• Plasma operation begins early to mid April 2003• Physics operation through mid June 2003

– Test modifications to ICRF antennas– Test new control coils

• Alternator inspection August 2003 (approx 3 months)• Installation of LH launcher (approx 6 weeks)• Plasma operation for 21 weeks in FY04

PAC Meeting 02/20-02/21 2003