Stav Fyziky Plazmatu AV R, V V I Tender

The Main Stui Function Is A Reliable Line-average Electron Plasma Density Measurement. The Interferometric System Measures The Differential Phase Reached By Two Probing Waves Of Close Frequencies Propagating Through Hot (up To 10 Kev) And Relatively Dense (1018 M-3 At The Edge Up To 1021 M-3 In The Core) Tokamak Plasmas. The Measured Phase Values Correspond To The Line-average Electron Plasma Density Along The Measurement Chord (probing Wave Path). Real-time Phase/density Measurement Should Be Provided, Being Also Used As An Input For The Feed-back Plasma Density Control System. As It Was Mentioned, The Discussions In The Context Of The Preliminary Market Consultations Would Be Focused On Different Topics. One Of These Topics Is The Stui Microwave Hw Design. Due To Complexity Of The Mentioned Topic And Special Operational Conditions, The Requirements For The Stui Should Be Specified. The Main Requirements Are Reliability Of The Line-average Electron Density Measurement During The Full Plasma Discharge Time, Single-chord Unambiguous Interferometry Based On A Differential Phase Measurement And To Be Insensitive To The Vertical Plasma Position (within The Range Of Plasma Shift Of Few Cm). Requirements And Limitations For The Stui Could Be Divided In Two Categories. The First Of Them Are Requirements On Interferometric Measurement Values And Could Be Formulated As Follows: Measured Density Range 5*1018 M-3 - 8 *1020 M-3, Precision Of The Phase Measurement About 2.2*1018 M-3 (in The Term Of Phase It Is About 1o), The Value Of The Phase Noise At The Stui Output Less Than -100 Dbc/hz At 10 Khz, Time Response Of The Measurement Shorter Than 500 Μs (> 2 Khz). The Second Includes Hardware Requirements And Limitations Given By The Tokamak Operation And Could Be Written As Follows: Possibility To Change The Probing Wave Frequency Before Measurement (switching Between Frequency Set-ups Is Preferred); Integration With The Feed-back Plasma Density Control System; To Provide Precise Measurements At Tokamak Operation Temperatures Up To 500 Oc And Under High Neutron Flux Up To 5*1013 N/cm2/s Near The Vacuum Vessel And For A Short Time Of The Discharge Duration Only; Galvanic Insulation From Other Devices And Tokamak Sub-systems. Note That Expected Power Losses Given By Propagation Of The Probing Wave In A Dense Plasma Are About 15 Db (in The Worst-case Scenario). Several Powerful Devices Such As Nbis (neutral Beam Injectors) Of About 1-2 Mw/unit (up To 3 Units Are Expected) And Ecrh (electron Cyclotron Resonance Heating) Of Up To 10 Mw At Expected Frequencies 140 Ghz Will Be Utilized In The Compass-u Tokamak. It Adds An Extra Requirement – Stui Should Not Be Sensitive To Operation Of These Systems. Due To High Neutron Fluxes Near The Tokamak, Sensitive Electronics Of The Interferometer Should Be Placed In A Safe Zone (the Diagnostic Area Behind Walls Of The Tokamak Hall). Connection Of The Measuring Place And This Electronics Will Be Ensured By About 35 M Of Waveguides With Several Mitter Bands. The Main Requirement For The Waveguide Route Is As Low Level Of Attenuation As Possible. The Critical Level Of The Total Attenuation Is About 15 Db (attenuation Of The Waveguides, Waveguide Transformers And Mitter Bands). The Current Reference Option Is A Use Of Quasi Optical Waveguides. Their Suitability, Possible Routing But Also Other Waveguide Options Can Be Discussed. Although The Port Plug Design Has Been Already Proposed, An Exact Set-up Inside The Port, Operation Of The Microwave System At Elevated Temperatures And Precision Of The Measurement At These Conditions Are Among The Points To Be Clarified. See More Details In The Dedicated Presentation About Sub-thz Unambiguous Interferometer For Compass-u, Prepared For These Preliminary Market Consultations And Publicly Available On The Submitter's Website (follow Section Called Additional Information)..