The Enormous Toroidal Plasma Device (ETPD) is an experimental physics device housed at the Basic Plasma Science Facility at University of California, Los Angeles (UCLA). It previously operated as the Electric Tokamak (ET) between 1999 and 2006 and was noted for being the world's largest tokamak[1] before being decommissioned due to the lack of support and funding.[2] The machine was renamed to ETPD in 2009. At present, the machine is undergoing upgrades to be re-purposed into a general laboratory for experimental plasma physics research.
The Electric Tokamak (ET) was the last of a series of small tokamak machines built in 1998 under the direction of principal investigator and designer, Robert Taylor, a UCLA professor. The machine was designed to be a low field (0.25 T) magnetic confinement fusion device with a large aspect ratio. It is composed of 16 vacuum chambers made of 1-inch thick steel, with a major radius of 5 meters and a minor radius of 1 meter. The ET was the largest tokamak ever built at its time, with a vacuum vessel slightly bigger than that of the Joint European Torus.
The first plasma was achieved in January 1999. The ET is capable of producing a plasma current of 45 kiloamperes and can produce a core electronplasmatemperature of 300 eV.[3][4]
Four sets of independent coils are necessary for OH (ohmic heating) current drive, vertical equilibrium field, plasma elongation and plasma shaping (D or reverse-D). The OH system provides 10 V·s using a 10 kA power supply. Up to 0.1 T of vertical field can be applied for horizontal control and this is more than sufficient for all plasma configurations, including high beta. An additional set of coils provide a small horizontal field to correct for error field and to stabilize the plasma vertically. All the coils are located outside the vessel and are constructed out of aluminium.
A Rogowski probe outside the vessel and sets of Hall probes inside the vessel are used to monitor plasma current, position and shaping and are used in the control feedback loop. The poloidal system was designed using an in-house equilibrium code as well as a variety of other codes in order to cross-check computations and to assess the stability of the resulting plasma.
In 2006, the ET had run out of funding and was decommissioned following the retirement of Taylor. Factors leading to loss of funding are attributed to the lack of extensive plasma diagnostics, its large size, and its place in the politics of fusion. When it was operating, the ET was funded mostly by the Department of Energy (DOE).[2]
As the Enormous Toroidal Plasma Deviceedit
In 2009, the Electric Tokamak (ET) was renamed to the Enormous Toroidal Plasma Device (ETPD) and was re-purposed for basic plasma research. A lanthanum hexaboride (LaB6) plasma source was developed for the ETPD[5] (similar to the one used in the Large Plasma Device), and is capable of producing a long column of magnetized plasma (~100 m) that winds itself multiple times along the toroidal axis of the machine. The plasma column was shown to be current-free and terminates on the neutral gas within the chamber without touching the machine walls.[6]
The typical operational parameters of the ETPD[7] are:
The ETPD is currently in the process of being upgraded (i.e. larger sources,[8] better diagnostic capabilities) to support a wide range of plasma physics experiments.
See alsoedit
Large Plasma Device, a linear plasma device housed in the same facility as the ETPD
Referencesedit
^(PDF). Archived from the original (PDF) on 2016-03-03. Retrieved 2020-03-31.
^ abTaylor, Robert John (2014). "UCLA Tokamak Program Close out Report". doi:10.2172/1117531. OSTI 1117531. {{cite journal}}: Cite journal requires |journal= (help)
^Taylor, R. J.; Gauvreau, J.-L.; Gilmore, M.; Gourdain, P.-A.; LaFonteese, D. J.; Schmitz, L. W. (2002). "Initial plasma results from the Electric Tokamak". Nuclear Fusion. 42 (1): 46. Bibcode:2002NucFu..42...46T. doi:10.1088/0029-5515/42/1/307. ISSN 0029-5515. S2CID 250866429.
^Cooper, C. M.; Gekelman, W.; Pribyl, P.; Lucky, Z. (16 Aug 2010). "A new large area lanthanum hexaboride plasma source". Review of Scientific Instruments. 81 (8): 083503–083503–8. Bibcode:2010RScI...81h3503C. doi:10.1063/1.3471917. ISSN 0034-6748. PMID 20815604.
^Cooper, C. M.; Gekelman, W. (24 Jun 2013). "Termination of a Magnetized Plasma on a Neutral Gas: The End of the Plasma". Physical Review Letters. 110 (26): 265001. Bibcode:2013PhRvL.110z5001C. doi:10.1103/PhysRevLett.110.265001. PMID 23848883.
^DeRose, K. L.; Cooper, C.; Pribyl, P.; Gekelman, W. (2008). (PDF). Archived from the original (PDF) on 27 July 2018. Retrieved 26 Jul 2008.
^Carter, T. A.; Dorfman, S.; Vincena, S.; Gekelman, W.; Klein, K.; Howes, G. G. "High beta, hot ion, magnetized laboratory plasmas in LAPD and ETPD: prospects for studying processes relevant to space and astrophysical plasmas". CiteSeerX10.1.1.709.6176. {{cite journal}}: Cite journal requires |journal= (help)
External linksedit
with photos.
February 25, 2024
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The Enormous Toroidal Plasma Device ETPD is an experimental physics device housed at the Basic Plasma Science Facility at University of California Los Angeles UCLA It previously operated as the Electric Tokamak ET between 1999 and 2006 and was noted for being the world s largest tokamak 1 before being decommissioned due to the lack of support and funding 2 The machine was renamed to ETPD in 2009 At present the machine is undergoing upgrades to be re purposed into a general laboratory for experimental plasma physics research Contents 1 As the Electric Tokamak 1 1 Decommission in 2006 2 As the Enormous Toroidal Plasma Device 3 See also 4 References 5 External linksAs the Electric Tokamak editElectric Tokamak nbsp A top view of the Electric Tokamak Device typeTokamakLocationLos Angeles California USAffiliationUCLATechnical specificationsMajor radius5 m 16 ft Minor radius1 m 3 ft 3 in Plasma volume188 m3Magnetic field0 25 T 2 500 G Heating power2 MWPlasma current30 45 kAHistoryYear s of operation1999 2006The Electric Tokamak ET was the last of a series of small tokamak machines built in 1998 under the direction of principal investigator and designer Robert Taylor a UCLA professor The machine was designed to be a low field 0 25 T magnetic confinement fusion device with a large aspect ratio It is composed of 16 vacuum chambers made of 1 inch thick steel with a major radius of 5 meters and a minor radius of 1 meter The ET was the largest tokamak ever built at its time with a vacuum vessel slightly bigger than that of the Joint European Torus The first plasma was achieved in January 1999 The ET is capable of producing a plasma current of 45 kiloamperes and can produce a core electron plasma temperature of 300 eV 3 4 Four sets of independent coils are necessary for OH ohmic heating current drive vertical equilibrium field plasma elongation and plasma shaping D or reverse D The OH system provides 10 V s using a 10 kA power supply Up to 0 1 T of vertical field can be applied for horizontal control and this is more than sufficient for all plasma configurations including high beta An additional set of coils provide a small horizontal field to correct for error field and to stabilize the plasma vertically All the coils are located outside the vessel and are constructed out of aluminium A Rogowski probe outside the vessel and sets of Hall probes inside the vessel are used to monitor plasma current position and shaping and are used in the control feedback loop The poloidal system was designed using an in house equilibrium code as well as a variety of other codes in order to cross check computations and to assess the stability of the resulting plasma Like most tokamaks the machine uses a combination of RF heating and neutral beam injection to drive and shape the plasma Decommission in 2006 edit In 2006 the ET had run out of funding and was decommissioned following the retirement of Taylor Factors leading to loss of funding are attributed to the lack of extensive plasma diagnostics its large size and its place in the politics of fusion When it was operating the ET was funded mostly by the Department of Energy DOE 2 As the Enormous Toroidal Plasma Device editIn 2009 the Electric Tokamak ET was renamed to the Enormous Toroidal Plasma Device ETPD and was re purposed for basic plasma research A lanthanum hexaboride LaB6 plasma source was developed for the ETPD 5 similar to the one used in the Large Plasma Device and is capable of producing a long column of magnetized plasma 100 m that winds itself multiple times along the toroidal axis of the machine The plasma column was shown to be current free and terminates on the neutral gas within the chamber without touching the machine walls 6 The typical operational parameters of the ETPD 7 are Density n 3 1013 cm 3 Electron Temperature 5 eV lt Te lt 30 eV Ion Temperature 1 eV lt Ti lt 16 eV Background field B 250 gauss 25 mT Plasma beta b 1The ETPD is currently in the process of being upgraded i e larger sources 8 better diagnostic capabilities to support a wide range of plasma physics experiments See also editLarge Plasma Device a linear plasma device housed in the same facility as the ETPDReferences edit 2002 03 Annual Report PDF Archived from the original PDF on 2016 03 03 Retrieved 2020 03 31 a b Taylor Robert John 2014 UCLA Tokamak Program Close out Report doi 10 2172 1117531 OSTI 1117531 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Initial Plasmas in the Electric Tokamak Taylor R J Gauvreau J L Gilmore M Gourdain P A LaFonteese D J Schmitz L W 2002 Initial plasma results from the Electric Tokamak Nuclear Fusion 42 1 46 Bibcode 2002NucFu 42 46T doi 10 1088 0029 5515 42 1 307 ISSN 0029 5515 S2CID 250866429 Cooper C M Gekelman W Pribyl P Lucky Z 16 Aug 2010 A new large area lanthanum hexaboride plasma source Review of Scientific Instruments 81 8 083503 083503 8 Bibcode 2010RScI 81h3503C doi 10 1063 1 3471917 ISSN 0034 6748 PMID 20815604 Cooper C M Gekelman W 24 Jun 2013 Termination of a Magnetized Plasma on a Neutral Gas The End of the Plasma Physical Review Letters 110 26 265001 Bibcode 2013PhRvL 110z5001C doi 10 1103 PhysRevLett 110 265001 PMID 23848883 DeRose K L Cooper C Pribyl P Gekelman W 2008 Measurement of the Plasma Beta in the Enormous Toroidal Plasma Device ETPD PDF Archived from the original PDF on 27 July 2018 Retrieved 26 Jul 2008 Carter T A Dorfman S Vincena S Gekelman W Klein K Howes G G High beta hot ion magnetized laboratory plasmas in LAPD and ETPD prospects for studying processes relevant to space and astrophysical plasmas CiteSeerX 10 1 1 709 6176 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help External links edit Installation and Initial Testing of the Electric Tokamak Folded Waveguide with photos UCLA Electric Tokamak Homepage UCLA Tokamak Research Retrieved from https en wikipedia org w index php title Enormous Toroidal Plasma Device amp oldid 1204407638, wikipedia, wiki, book, books, library,
