 COMPASS tokamak vacuum chamber | |
| Device type | Tokamak |
|---|---|
| Location | Prague,Czech Republic |
| Affiliation | Czech Academy of Sciences |
| Technical specifications | |
| Major radius | 0.56 m (1 ft 10 in) |
| Minor radius | 0.23 m (9.1 in) |
| Magnetic field | 0.9–2.1 T (9,000–21,000 G) |
| Heating power | 2 ×0.3 MW |
| Discharge duration | 0.5 s (pulsed) |
| Plasma current | 360 kA |
| History | |
| Year(s) of operation | 1992–2002 (inUK) 2006–2021 (inCZ) |
| Links | |
| Website | COMPASS Tokamak |
| Other links | |
COMPASS, short for Compact Assembly, is a compacttokamakfusion energy device originally completed at theCulham Science Centre in 1989, upgraded in 1992, and operated until 2002. It was designed as a flexible research facility dedicated mostly to plasma physics studies in circular and D-shapedplasmas.
When it was decommissioned at Culham, it was offered to the European Commission and found a new home at the Institute of Plasma Physics of theCzech Academy of Sciences inPrague where it began operations once again in 2006.[1][2][3][4] It officially ended its experimental runs on 20 August 2021 and was disassembled to leave room for a new device, COMPASS-U.[5]
The first plasma in COMPASS was produced in 1989 in a C-shapedvacuum vessel, i.e., in a simpler vessel with a circular cross-section. Pioneering experiments followed, including for example theITER-relevant tests ofmagnetic field correction with saddle coils forResonant magnetic perturbations (RMP) experiments or experiments with non-inductive current drive in plasma.
The operation of tokamak was restarted with a D-shaped vacuum vessel in 1992. The operation mode with high plasma confinement (H-mode) was achieved, which represents a reference operation ("standard scenario") for the ITER tokamak. The COMPASS tokamak is one of the smallest tokamaks able to operate in H-mode, with a major radius 0.6 m and height of approximately 0.7 m. Due to its size and shape, the COMPASS plasmas correspond to one tenth (in the linear scale) of the ITER plasmas. Besides COMPASS, there are only two operational tokamaks in Europe with ITER-like configuration capable of H-mode, theJoint European Torus (JET) at Culham and theASDEX Upgrade at theInstitut für Plasmaphysik inGarching, Germany.
In 2002, British scientists started alternative research on larger, spherical tokamakMAST. Operation of COMPASS was discontinued due to insufficient resources for the operation of both tokamaks, however, the planned research program was not complete. The European Commission and UKAEA sent COMPASS to the Institute of Plasma Physics inPrague in the autumn of 2004. The machine restarted operations in 2006 and operated continually until its last "shot" on 20 August 2021. During its operational time in Prague, COMPASS carried out 21,000 experimental shots.
After August 2021, COMPASS was disassembled to make way for a significantly larger machine, COMPASS-U (for Upgrade). Its construction is currently (May 2024) underway.
| Parameters | Values[6] | Values after planned upgrade in 2021[7] |
|---|---|---|
| Major radiusR | 0.56 m | 0.84 m |
| Minor radiusa | 0.23 m | 0.28 m |
| Plasma currentIp (max) | 360 kA | 2 MA |
| Magnetic fieldBT | 0.9 T - 2.1 T | 5 T |
| Vacuum pressure | 1×10−6 Pa | |
| Elongation | 1.8 | |
| Plasma shape | D, SND, elliptical, circular | |
| Pulse length(max) | ~ 0.5 s | 5 s |
| Beam heatingPNBI 40 keV | 2 × 0.3 MW | 4-5 MW |
https://iopscience.iop.org/article/10.1088/0741-3335/58/1/014015
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