Z machine 1096102 213497757 2008-05-19T16:44:12Z Potatoswatter 2769105 /* Z-Pinch Inertial Fusion Energy research */ finally found classification of organization at end of slides! :''This article is about the X-ray generator. For the Infocom virtual machine, see [[Z-machine]].'' [[Image:Z-machine480.jpg|thumb|right|440px|The Z machine at Sandia National Laboratory. Due to the extremely [[high voltage]], the power feeding equipment is submerged in concentric chambers of 2 megalitres (2,000 m³) of transformer oil and 2.3 megalitres (2,300 m³) of [[deionized water]], which act as [[Electrical insulation|insulator]]s. Nevertheless, the [[electromagnetic pulse]] when the machine is discharged causes impressive lightning, referred to as "arcs and sparks" or "flashover", which can be seen around many of the metallic objects in the room. Courtesy, Sandia National Laboratories]] The '''Z machine''' is the largest [[X-ray]] generator in the world and is designed to test materials in conditions of extreme temperature and pressure. Operated by [[Sandia National Laboratories]], it gathers data to aid in [[computer modeling]] of [[nuclear weapon]]s. The Z machine is located at Sandia's main site in [[Albuquerque, New Mexico|Albuquerque]], [[New Mexico]]. ==Operation overview== The Z machine fires a very powerful electrical discharge (several tens million-[[ampere]] for less than 100 [[second|nanoseconds]]) into an array of thin, parallel [[tungsten]] wires called a ''liner''. The high electrical current vaporizes the wires, transformed into a cylindrical [[Plasma (physics)|plasma]] curtain. Simultaneously, the [[current density]] induces a powerful [[magnetic field]] and their combination creates [[Lorentz force|Lorentz forces]] which radially compress the plasma into a [[z-pinch]] process. The imploding plasma produces a high temperature and an X-ray pulse which can create a [[shock wave]] in a target structure. The target structure is placed in a cavity inside the wires called a [[hohlraum]]. The powerful fluctuation in the magnetic field (an "[[electromagnetic pulse]]") also generates electric current in all of the metallic objects in the room (see picture at upper right). The vertical cylinder's axis is conventionally termed the ''z''-axis, hence the name "Z machine". Originally designed to supply 50 [[terawatt]]s of power in one fast pulse, technological advances resulted in an increased output of 290 terawatts, enough to study [[nuclear fusion]]. Z releases 80 times the world's electrical power output for a few billionths of a second; however, only a moderate amount of energy is consumed in each test (roughly equal to the electrical energy consumed by 100 U.S households in two minutes{{quantify|date=December 2007}}). [[Marx generator]]s are slowly charged with energy prior to firing. Sandia announced the fusing of [[deuterium]] in the Z machine on [[April 7]], [[2003]].<ref>[http://www.sandia.gov/news-center/news-releases/2003/nuclear-power/Zneutrons.html Z produces fusion neutrons, Sandia scientists confirm], Sandia's press release (April 7, 2003).</ref> This application could result in an efficient method to ignite a [[nuclear fusion]] reaction starting from a small capsule of [[deuterium]]. Unfortunately many technical difficulties — for instance the small quantity of [[deuterium]] that can be contained in the hohlraum and the practical impossibility to transfer the compressed capsule to a larger [[nuclear fuel]] reservoir — prevent the machine to be used this way, for the moment. Besides being used as an X-ray generator, the Z machine propelled small plates at 34 kilometres a second, faster than the 30 kilometres per second that Earth travels in its orbit around the [[Sun]], and three times [[escape velocity|Earth's escape velocity]].<ref>[http://www.sandia.gov/news-center/news-releases/2005/nuclear-power/z-saturn.html Z fires objects faster than Earth moves through space], Sandia's press release (June 6, 2005).</ref> It also successfully created a special, hyperdense "hot ice" known as [[ice VII]], by quickly compressing water to pressures of 70,000 to 120,000 [[Atmosphere (unit)|atmospheres]].<ref>[http://www.sandia.gov/news/resources/releases/2007/z-ice.html Ice created in nanoseconds by Sandia’s Z machine], Sandia's press release (March 15, 2007).</ref> At the end of 2005, the Z machine produced plasmas with announced temperatures in excess of 2 billion [[kelvin]]s (2 GK, 2×10<sup>9</sup> K) or 3.6 billion [[Fahrenheit|°F]], even reaching a peak at 3.7 billion K or 6.6 billion °F.<ref>[http://www.sandia.gov/news-center/news-releases/2006/physics-astron/hottest-z-output.html Sandia’s Z machine exceeds two billion degrees Kelvin], Sandia's press release (March 8, 2006).</ref><ref name="haines_a" /><ref name="haines_b" /> It was achieved in part by replacing the tungsten wires by thicker steel wires. This temperature, which enables a 10% to 15% efficiency in converting electrical energy to soft x-rays, was much higher than anticipated (3 to 4 times the [[kinetic energy]] of the incoming wires on axis). Thus far, it is currently the highest man-made temperature ever achieved according to [[Guinness_World_Records|The Guinness Book Of Records]]. The origin of this extra energy still remains unexplained, but it has been theorized that small-scale [[magnetohydrodynamics|MHD]] turbulence and viscous damping would convert magnetic energy into thermal energy of the ions, which then would transfer their energy to the electrons through collisions.<ref name="haines_a">[http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000096000007075003000001 Abstract of Malcolm Haines' paper] published in [[Physical Review Letters]] 7, Vol.96 (February 24, 2006).</ref><ref name="haines_b">[http://www.mhdprospects.com/pdf/comments_on_haines_paper.pdf Analysis of Malcolm Haines' paper] by [[Jean-Pierre Petit]] (June 25, 2006).</ref> == Prospects == The ultra high temperatures reached in 2005 (2.66 to 3.7 billion Kelvin) are greatly higher than those required for the classical [[hydrogen]], deuterium and [[tritium]] fusion envisaged hitherto. They could allow in theory, if not in practice, the fusion of light hydrogen atoms with heavier atoms such as [[lithium]] or [[boron]]. These two possible fusion reactions do not produce [[neutron|neutrons]] thus no [[Radioactive decay|radioactivity]] nor [[Radioactive waste|nuclear waste]], so they open for the first time the possibility of a man-made clean [[aneutronic fusion]]. But it could also represent a potential [[nuclear proliferation]] problem, because [[pure fusion weapon|pure fusion weapons]] could be made if the little [[Nuclear fission|fission]] [[A-bomb]] used classically for ignition of [[H-bomb|H-bombs]] were replaced by a Z pinch [[detonator]], fed with a compact [[pulsed power]] generator fast enough (a [[Explosively pumped flux compression generator#Disc generators|disc generator]] for example).<ref>[http://www.princeton.edu/~globsec/publications/pdf/7_2Jones.pdf The Question of Pure Fusion Explosions Under the CTB], Science & Global Security, Vol.7, Appendix D (1998).</ref> A $60 million (raised to $90 million) retrofit program called ZR (Z Refurbished) was announced in 2004 to increase the power by 50%. The Z machine was dismantled in July of 2006 for this upgrade, including the installation of newly designed hardware and components and more powerful [[Marx generator]]s. The de-ionized water section of the machine has been reduced to about half its old size while the oil section has been expanded significantly in order to house larger intermediate storage lines (i-stores) and new laser towers, which used to sit in the water section. The refurbishment was completed in October of 2007.<ref> [http://www.sandia.gov/news/resources/releases/2007/zaccelerator.html Successful 'shots' signal re-opening of Sandia's giant Z accelerator], Sandia's press release (17 October, 2007).</ref> The newer Z machine can now shoot 27 million amperes instead of 18 million amperes previously, still in 95 nanoseconds. The radiated power has been raised to 350 terawatts and the X-ray energy output to 2.7 [[megajoule]]s. However the maximum temperature the new version could reach with the same record holder [[stainless steel]] wire-array liner used in 2005 is not known yet. Sandia's roadmap includes another future Z machine version called ZN (Z Neutron) to test higher yields in fusion power and automation systems. ZN is planned to give between 20 and 30 MJ of hydrogen fusion power with a shot per hour thanks to Russian [[Linear Transformer Driver]] (LTD) replacing the current Marx generators.<ref>[http://www.sandia.gov/LabNews/070427.html Rapid-fire pulse brings Sandia’s Z method closer to goal of developing high-yield fusion reactor], Sandia's press release (April 27 , 2007).</ref> After 8 to 10 years of operation, ZN would become a transmutation pilot plant capable of a fusion shot every 100 seconds.<ref>[http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/2006/067148.pdf Z-Inertial Fusion Energy: Power Plant Final Report FY 2006], Sandia Report SAND2006-7148 (October 2006).</ref> The next step planned would be the Z-IFE (Z-inertial fusion energy) test facility, the first true z-pinch driven prototype fusion power plant. It is suggested it would integrate Sandia's latest designs using LTDs. Sandia labs recently proposed a conceptual 1 petawatt (10<sup>15</sup> watts) LTD Z-pinch power plant, where the electric discharge would reach 70 million amperes.<ref>W.A. Stygar ''et al.'', [http://www.sandia.gov/pulsedpower/prog_cap/pub_papers/accelerator_architecture_PRSTAB_2007.pdf Architecture of petawatt-class z-pinch accelerators] (October 2007).</ref> [[Image:Petawatt_LTD_z_pinch.png|thumb|center|500px|Proposed model of a 1000 terawatt LTD-based z-pinch accelerator.<br> 104 m diameter, 70 milion amperes, 24 megavolts. Human being (in the middle) for scale.]] One should however note all these announced fusion systems make use of the X-ray radiation to heat a hohlraum in order to indirectly ignite fusion reaction of [[isotopes of hydrogen]]. The unexpected ultra high temperature achieved recently is not taken into account yet for any possible use of direct aneutronic fusion reactions ([[proton|p]]–[[lithium|<sup>7</sup>Li]] or p–[[boron|<sup>11</sup>B]]) which, if proven practicable, would imply reconsidering some proposed designs. ==Z-Pinch Inertial Fusion Energy program== {{Further|[[Inertial fusion power plant]]}} The [[Sandia National Laboratories|Sandia Laboratories]] Z-IFE project<ref>An introduction to the Z-IFE project may be found [http://fire.pppl.gov/fpa05_olson.pdf here].</ref> aims to solve the practical difficulties in harnessing fusion power. Major problems include producing energy in a single Z-pinch shot, and quickly reloading the reactor after each shot. By their early estimates, an implosion of a fuel capsule every 10 seconds could economically produce 300&nbsp;MW of fusion energy. ==Notes and references== {{Reflist|1}} ==See also== * [[Sandia National Laboratories]] * [[Fusion power]] * [[Stockpile stewardship]] * [[Pulsed power]] * [[Inertial fusion power plant]] ==External links== * [http://zpinch.sandia.gov/ Z Machine Home Page] * [http://observer.guardian.co.uk/life/story/0,6903,416412,00.html "A machine called Z"] * [http://www.aip.org/enews/physnews/2006/split/767-3.html ''Physics News Update''], [[February 28]], [[2006]] * [http://www.mystrangenewmexico.com/the-columns/2007/2/22/black-holes-at-home.html "The Z Machine and the Possibility of Miniature Black Holes"] {{fusion experiments}} [[Category:Nuclear research centers]] [[Category:Fusion power]] [[Category:Fusion reactors]] [[Category:Nuclear stockpile stewardship]] [[de:Z-Maschine]] [[fr:Z machine]] [[id:Mesin Z]] [[it:Z machine]] [[pt:Máquina Z]] [[fi:Z-kone]]