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| PISCES Upgrade |
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| PISCES Upgrade |
Much of the PISCES Upgrade hardware has been completed. Photos and a description of the existing hardware are now available.
PISCES-Upgrade is to be an experimental plasma facility at the University of California, San Diego (UCSD). This facility will investigate heat flux plasmas that are representative of the ITER plasma conditions. The Boeing Company is under subcontract to UCSD to design and fabricate the new components and systems necessary to upgrade the present experiment, the PISCES-B, to the capability of the PISCES-Upgrade. Dr. Russell Doerner is the UCSD Program manager and Lester Waganer is the Boeing Program Manager.
The existing PISCES-A and PISCES-B facilities use reflex arc discharges with electrons emitted from a hot LaB6 disk at one end of the machines. These electrons are radially confined to a cylindrical configuration with external solenoidal magnetic fields. The electrons are reflected by the cathode and plasma target plate at opposite ends of the cylindrical machine. The reflexing electrons collide with and ionize a neutral gas to form plasma ions that are drawn to the negatively-charged target plate. This is shown schematically in the figure below.
The UCSD PISCES team proposed a change in the magnetic configuration from a cylinder to a cusp to improve the performance of the PISCES-Upgrade machine. The arrangement of the present magnets will be altered to obtain a cusp field. The larger-surface-area annular cathode will help improve the system performance. The new hardware will include a new annular cathode, two cusp-shaped anodes, longer beam tubes, and new reflecting and target dump plates. The maximum heat flux on the dump plates is 15 MW/m2 and 7.5 MW/m2 on the anodes.
The design PISCES-Upgrade was completed by Boeing and the procurement of the hardware is nearly complete. The hardware includes the annular cathode, the two cusp-shaped anodes, two beam tubes, the reflecting dump plate, the target dump plate, and the assembly stand. All the of the hardware is now in house, with the exception of the cusp-shaped anodes. The machining of the high-power anodes was completed in August 1997 and they were delivered to St. Louis. A photograph of the machined anodes are shown below. The final operation is to close out the coolant channels and attach the inlet and outlet coolant tubes with a structural layer of electroplated copper. The anodes are constructed from a forged copper billet with final dimensions of 24 inches in diameter and 9.3 inches high (no welds). Links to more detailed pictures can be found at the end of this page.
Shown below is a photo of the machined copper parts of the Reflecting Dump Plate before being brazed together. This Reflecting Dump Plate is actually at the end opposite to the target. But, depending upon the magnetic field arrangement, this dump plate can have up to 15 MW/m2 on its interior surface facing the plasma (not shown). This view is from the outside of the dump plate looking at the details of the integral heat exchanger. To give the viewer a sense of size, a six-inch scale is shown below the parts. This view shows the interior fins of the heat exchanger and the matching cover plate. Two end plugs are also shown that allow an easier method of machining the heat exchanger grooves. Cooling water will enter one of the holes in the cover plate, traverse the heat exchanger, and exit the other hole in the cover plate. The small, stainless steel fitting laying on the main flange is a gas feed line was brazed into the plate by our vendor.
There is also a virtual lab tour through the laboratory facility at UCSD where the current PISCES-B is located and ultimately where the PISCES-Upgrade experimental hardware will be installed.