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Encyclopedia > HiPER

HiPER is an experimental laser-driven inertial confinement fusion (ICF) device currently undergoing preliminary design for possible construction in the European Union starting around 2010. HiPER is the first experiment designed specifically to study the "fast ignition" approach, which uses much smaller lasers than conventional designs, yet produces fusion power outputs of about the same magnitude. This offers a total "fusion gain" that is much higher than devices like the National Ignition Facility, and an order of magnitude reduction in overall cost. Inertial confinement fusion using lasers rapidly progressed in the late 1970s and early 1980s from being able to deliver only a few joules of laser energy (per pulse) to a fusion target to being able to deliver tens of kilojoules to a target. ... For the film, see 2010: The Year We Make Contact. ... A construction worker inside NIFs 10 meter target chamber. ...

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Description

The basic goal of any ICF system is to quickly heat the outer layers of a "target" with a "driver laser" (or in some cases, heavy ions). This heat explosively vaporizes the outer surface of the target and heat it into a plasma. The rapid expansion of the resulting plasma "explodes" off the target, pushing the rest of the target in the opposite direction due to Newton's Third Law. This compresses the interior of the target to very high density (many times the density of lead for instance), while at the same time creating a shock wave traveling into the center. When the shock wave reaches the center of the target its energy further heats and compresses the very center of the compressed fuel, raising the temperature at that spot to millions to hundreds of millions of kelvins. The combination of heat and compression raises the internal temperature of the target to the point where fusion reactions can occur in the center. Look up plasma in Wiktionary, the free dictionary. ... Newtons laws of motion are the three scientific laws which Isaac Newton discovered concerning the behaviour of moving bodies. ... General Name, Symbol, Number lead, Pb, 82 Chemical series poor metals Group, Period, Block 14, 6, p Appearance bluish white Atomic mass 207. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ...


In the case of HiPER, this driver laser system is fairly conventional, but seemingly undersized. The driver consists of a number of "beamlines" (sources suggest either 20 or 96) containing Nd:glass laser amplifiers at one end of the building. Just prior to firing, the glass is "pumped" to a high-energy state with a series of Xenon flash tubes, causing a population inversion of the niobium atoms in the glass. This readies them for amplification via simulated emission when a small amount of laser light, generated externally, is fed into the beamlines. The glass is not particularly effective at transferring power into the beam, so in order to get as much power as possible back out the beam is reflected through the glass several times in a mirrored cavity, each time gaining more power. When this process is complete, a pockels cell "switches" the light out of the cavity. Laser pumping is the act of energy transfer from an external source into the laser gain medium. ... In physics, specifically statistical mechanics, the concept of population inversion is of fundamental importance in laser science because the production of a population inversion is a necessary step in the workings of a laser. ... Experiment using a (likely argon) laser. ... The Pockels effect, or Pockels electro-optic effect, is the production of birefringence in an optical medium induced by a slowly-varying electric field. ...


From there it is fed into a very long spatial filter, effectively a telescope that focuses the beam into a spot some distance away. A small pinhole located at the focal point cuts of any "stray" light caused by inhomogeneities in the laser beam, which are impossible to avoid. It is the use of spatial filters that lead to the long beamlines seen in ICF laser devices. In the case of HiPER, the filters take up about 50% of the overall length. The beam width at exit from the beamlines is about 20 cm across. A spatial filter is an optical device which uses the principles of Fourier optics to alter the structure of a beam of coherent light or other electromagnetic radiation. ...


When this process is complete the laser light enters the experimental chamber, lying at one end of the building. Here it is reflected off of a series of deformable mirrors that help correct remaining imperfections in the wavefront, and then feed them into the target chamber from all angles. Since the overall distance from the ends of the beamlines to different points on the target chamber is different, delays are introduced on the individual paths to ensure they all reach the center of the chamber at the same time, within about a picosecond. The target, a fusion fuel pellet about 1 mm in diameter in the case of HiPER, lies at the center of the chamber.

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Fast Ignition and HiPER

In traditional ICF devices the driver laser is used to compress the target to very high densities. The shock wave created by this process heats the interior of the compressed fuel. If the compression is symmetrical enough the temperature can rise enough to create conditions close to the Lawson criterion, leading to significant fusion energy production. If the rate is high enough, the energy created in these reactions will heat the surrounding fuel to similar temperatures, causing them to undergo fusion as well. In this case, known as "ignition", a significant portion of the fuel will undergo fusion and release large amounts of energy. Ignition is the basic goal of any fusion device. In nuclear fusion research, the Lawson criterion, first derived by John D. Lawson in 1957, is an important general measure of a system that defines the conditions needed for a fusion reactor to reach ignition, that is, that the heating of the plasma by the products of the fusion reactions...


The amount of laser energy needed to effectively compress the targets to ignition conditions has grown rapidly. In the "early days" of ICF research in the 1970s it was believed that something on the order of 100 kilojoules (Kj) would suffice, and a number of experimental lasers were built in order to reach these power levels. When the did, a series of problems, typically related to the homogeneity of the collapse, turned out to seriously disrupt the implosion symmetry and lead to much cooler core temperatures that originally expected. Through the 1980s the estimated energy required to reach ignition grew into the megajoule range, which appeared to make ICF impractical for fusion energy production. For instance, the National Ignition Facility (NIF) uses about 330 MJ of electrical power to pump the driver lasers, and in the best case is expected to produce about 100 MJ of fusion power output. Without dramatic gains in output, such a device would never be a practical generator. The joule (symbol J, also called newton metre, or coulomb volt) is the SI unit of energy and work. ... A construction worker inside NIFs 10 meter target chamber. ...


It is important to remember that the Lawson criterion is a "triple product" of density, temperature and confinement time. In the past, ICF has attempted to reach ignition through compression, using that to generate the required temperatures via the shock wave formation. It is the formation of high enough density and temperature coupled with a shock wave of the required energy which converges at the core at precisely the right time which has been the primary problem in ICF work. In the recent "fast ignition" approach heating is provided externally, and shock wave formation is no longer as important (if at all). Instead, fast ignition reaches the Lawson conditions via the direct formation of a hot spot "spark" using another separate laser.


In HiPER, the compression provided by the driver is "good", but not nearly that created by larger devices like NIF; HiPER's driver is about 200 kJ and produces densities of about 300 g/cm³, about one-third that of NIF, and about the same as generated by the earlier NOVA laser of the 1980s. For comparison, lead is about 11 g/cm³, so this represents a considerable amount of compression, notably when one considers the target's interior contained light D-T fuel. The Nova laser was a laser built at the Lawrence Livermore National Laboratory in 1984 and which conducted advanced inertial confinement fusion experiments until its dismantling in 1999. ... General Name, Symbol, Number lead, Pb, 82 Chemical series poor metals Group, Period, Block 14, 6, p Appearance bluish white Atomic mass 207. ...


How to heat the fuel at that point is still a matter for further research. One approach uses a short pulse from an extremely high power laser to heat the plasma outside the dense "core", essentially burning a hole through it and exposing the dense fuel inside. Another approach, tested successfully on the GEKKO XII laser in Japan, uses a small gold cone that protects a small area of the target from the plasma, leaving a hole in the plasma mechanically. GEKKO XII is a high-power 12-beam neodymium doped glass laser at the Osaka Universitys Institute for Laser Engineering completed in 1983, which is used for high energy density physics and inertial confinement fusion research. ...


In either case another very-short (~100 picoseconds) ultra-high-power (~70 kJ, 1 PW) laser pulse follows, aimed through the hole in the plasma at the core. The light from this pulse interacts with the fuel, generating a shower of high-energy (3.5 MeV) relativistic electrons that are driven into the fuel. It is not currently clear how quickly the electrons stop in the fuel load; while this is known for matter under normal pressure, but not the ultra-dense conditions of the compressed fuel. The electrons heat a spot on one side of the dense core, and if this heating is localized enough it is expected to drive the area well beyond ignition energies and resulting in a burn with significant fusion gains.


The overall efficiency of this approach is many times that of the conventional approach. Since the devices built to date are not intended for power production, the efficiency is typically measured in terms of fusion power produced for a given amount of final laser power. In the case of NIF the laser generates about 4 MJ of infrared power that is converted into about 1.8 MJ of x-rays, causing ignition that provides about 100 MJ of energy. This corresponds to a "fusion gain" of about 50. If one uses the baselines assumptions for the current HiPER design, the two lasers (driver and heater) produce about 270 kJ in total, yet generate 25 to 30 MJ, a gain of about 100. Not only does this theoretically outperform NIF, the smaller lasers are much less expensive to build. Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ...

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Current Status

HiPER has now completed a preliminary study, outlining possible approaches and arguments for its construction. If successful, which will be known in mid-2007, a three-year period of detailed design would start.


In parallel, the HiPER project also proposes to build smaller laser systems with higher repetition rates. The high powered light sources used to pump the laser amplifier glass causes it to deform, and it cannot be fired again until it cools off. HiPER proposes to build a demonstrator system producing 10 kJ at 1 Hz or 1 kJ at 10 Hz depending on a design choice yet to be made. The best high-repetition lasers currently operating are much smaller; MERCURY at LLNL is about 70 J, HALNA in Japan at ~20 J, and LUCIA in France at ~10 J (??). HiPER's demonstrator would thus be between 100 and 1000 times as powerful as any of these.


In order to make a practical commercial power generator, the high-gain of a device like HiPER would have to be combined with a high-repetition rate laser. Additional areas of research needed include practical methods to carry the heat out of the target chamber for power production, protecting the device from the neutron flux generated by the fusion reactions, and the production of tritium from this flux in order to produce more fuel for the reactor. This article or section does not cite its references or sources. ... Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ...

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References

  • HiPER: a laser fusion facility for Europe
  • E-mail with Dr. AM (Mike) Dunne, one of the HiPER investigators.


  Fusion power  v·d·e 
Atomic nucleus | Nuclear fusion | Nuclear power | Nuclear reactor | Timeline of nuclear fusion
Plasma physics | Magnetohydrodynamics | Neutron flux | Fusion energy gain factor | Lawson criterion
Methods of fusing nuclei
List of fusion experiments

Magnetic confinement devices
ITER (International) | JET (European) | JT-60 (Japan) | Large Helical Device (Japan) | KSTAR (Korea) | EAST (China) | T-15 (Russia) | DIII-D (USA) | TFTR (USA) | NSTX (USA) | NCSX (USA) | Alcator C-Mod (USA) | LDX (USA) | PACER (USA) | H-1NF (Australia) | MAST (UK) | START (UK) | TCV (Switzerland) | DEMO (Commercial) The Sun is a natural fusion reactor. ... A semi-accurate depiction of the helium atom. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... A nuclear power station. ... Core of a small nuclear reactor used for research. ... Timeline of significant events in the study and use of nuclear fusion: 1929 - Atkinson and Houtermans used the measured masses of light elements and applied Einsteins discovery that E=mc² to predict that large amounts of energy could be released by fusing small nuclei together. ... A Plasma lamp In physics and chemistry, a plasma is an ionized gas, and is usually considered to be a distinct phase of matter. ... Magnetohydrodynamics (MHD) (magnetofluiddynamics or hydromagnetics), is the academic discipline which studies the dynamics of electrically conducting fluids. ... neutron flux n : the rate of flow of neutrons; the number of neutrons passing through a unit area in unit time via dictionary. ... The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state. ... In nuclear fusion research, the Lawson criterion, first derived by John D. Lawson in 1957, is an important general measure of a system that defines the conditions needed for a fusion reactor to reach ignition, that is, that the heating of the plasma by the products of the fusion reactions... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Magnetic Fusion Energy (MFE) is a sustained nuclear fusion reaction in a plasma that is contained by magnetic fields. ... A split image of the largest tokamak in the world, the JET, showing hot plasma in the right image during a shot. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Stellarator magnetic field and magnets A stellarator is a device used to confine a hot plasma with magnetic fields in order to sustain a controlled nuclear fusion reaction. ... Reversed-Field Pinch is a toroidal magnetic confinement scheme. ... A Field-Reversed Configuration (FRC) is a device developed for magnetic fusion energy research that confines a plasma on closed magnetic field lines without a central penetration. ... A Levitated Dipole is a unique form of fusion reactor technology using a solid superconducting torus, magnetically levitated in the reactor chamber. ... Inertial confinement fusion using lasers rapidly progressed in the late 1970s and early 1980s from being able to deliver only a few joules of laser energy (per pulse) to a fusion target to being able to deliver tens of kilojoules to a target. ... In inertial confinement fusion (ICF), nuclear fusion reactions are initiated by heating and compressing a target – a pellet that most often contains deuterium and tritium – by the use of intense laser or ion beams. ... The Z machine at Sandia National Laboratories in Albuquerque, New Mexico. ... Bubble fusion or sonofusion is the common name for a nuclear fusion reaction hypothesized to occur during sonoluminescence, an extreme form of acoustic cavitation; officially, this reaction is termed acoustic inertial confinement fusion (AICF) since the inertia of the collapsing bubble wall confines the energy causing a rise in temperature. ... U.S. Patent 3,386,883 - fusor — June 4, 1968 The Farnsworth–Hirsch Fusor, or simply fusor, is an apparatus designed by Philo T. Farnsworth to create nuclear fusion. ... Muon-catalyzed fusion is a process allowing nuclear fusion to take place at room temperature. ... Pyroelectric fusion is a technique for achieving nuclear fusion by using an electric field generated by pyroelectric crystals to accelerate ions of deuterium (tritium might also be used someday) into a metal hydride target also containing detuerium (or tritium) with sufficient kinetic energy to cause these ions to fuse together. ... Cold fusion cell at the US Navy Space and Naval Warfare Systems Center, San Diego, CA (2005) By definition, Cold fusion is a nuclear fusion reaction that takes place at or near room temperature and normal pressure instead of the millions of degrees required for plasma fusion reactions. ... Experiments directed toward developing fusion power are invariably done with dedicated machines which can be classified according to the principles they use to confine the plasma fuel and keep it hot. ... Cutaway of the ITER Tokamak Torus in casing. ... Split image of JET with right side showing hot plasma during a shot. ... JT-60 (JT stands for Japan Torus) is the flagship of Japans magnetic fusion program, run by the Japan Atomic Energy Research Institute (JAERI), and the Naka Fusion Research Establishment in Ibaraki Prefecture, Japan. ... Categories: Stub | Nuclear technology ... The KSTAR, or Korean Superconducting Tokamak Advanced Reactor is a magnetic fusion device being built at the Korea Basic Science Institute in Daejon, South Korea. ... The Experimental Advanced Superconducting Tokamak (EAST, internally called HT-7U) is a project being undertaken to construct an experimental superconducting tokamak magnetic fusion energy reactor in Hefei, the capital city of Anhui Province, in eastern China. ... The T-15 is a Russian nuclear fusion research reactor, based on the (Russian-invented) tokamak design. ... DIII-D or D3-D is the name of a tokamak machine developed in the 1980s by General Atomics in San Diego, USA, as part of the ongoing effort to achieve magnetically confined fusion. ... The Tokamak Fusion Test Reactor (TFTR) was an experimental fusion test reactor built at Princeton Plasma Physics Laboratory (in Princeton, New Jersey) circa 1980. ... The National Spherical Torus Experiment (NSTX) is an innovative magnetic fusion device that was constructed by the Princeton Plasma Physics Laboratory (PPPL) in collaboration with the Oak Ridge National Laboratory, Columbia University, and the University of Washington at Seattle. ... The National Compact Stellarator Experiment (NCSX) is a plasma confinement experiment being conducted at the Princeton Plasma Physics Laboratory. ... Alcator C-Mod is a tokamak, a magnetically confined nuclear fusion device, at the MIT Plasma Science and Fusion Center. ... The Levitated Dipole Experiment (LDX) is a project devoted to researching a type of nuclear fusion which utilizes a floating superconducting torus to provide an axisymmetric magnetic field which is used to contain plasma. ... The PACER project, carried out at Los Alamos National Laboratory in the mid-1970s, explored the possibility of a fusion power system that would involve exploding small hydrogen bombs (fusion bombs)—or, as stated in a later proposal, fission bombs—inside an underground cavity. ... The H-1 flexible Heliac is a three field-period helical axis stellarator located in the Research School of Physical Sciences and Engineering at the Australian National University. ... The Mega Ampere Spherical Tokamak, or MAST experiment is a nuclear fusion experiment in operation at Culham since December 1999. ... The Small Tight Aspect Ratio Tokamak, or START was a nuclear fusion experiment that used magnetic confinement to hold plasma. ... Tokamak à Configuration Variable (TCV): inner view, with the graphite-claded torus. ... The word demo may refer to one of the following. ...


Inertial confinement devices
Laser driven:
ICF lasers in the United States: NIF (USA) | OMEGA laser (USA) | Nova laser (USA) | Novette laser (USA) | Nike laser (USA) | Shiva laser (USA) | Argus laser (USA) | Cyclops laser (USA) | Janus laser (USA) | Long path laser (USA) | 4 pi laser (USA)
ICF lasers in other nations: LMJ (France) | GEKKO XII (Japan) | ISKRA lasers (Russia) | Vulcan laser (UK) | Asterix IV laser (Czech Republic) | HiPER laser (European)
Non-laser driven:
Z machine (USA)
A construction worker inside NIFs 10 meter target chamber. ... The Laboratory for Laser Energetics (LLE) is a scientific research facility which is part of the University of Rochesters south campus, located in Rochester, New York. ... The Nova laser was a laser built at the Lawrence Livermore National Laboratory in 1984 and which conducted advanced inertial confinement fusion experiments until its dismantling in 1999. ... The Novette target chamber with two laser chains visible in background. ... Final amplifier of the Nike laser where laser beam energy is increased from 150 J to ~5 Kj by passing through a krypton/fluorine/argon gas mixture excited by irradiation with two opposing 670,000 volt electron beams. ... The Shiva laser was an extremely powerful 20 beam infrared neodymium glass (silica glass) laser built at Lawrence Livermore National Laboratory in 1977 for the study of inertial confinement fusion and long-scale-length laser-plasma interactions. ... Argus laser overhead view. ... The single beam Cyclops laser at LLNL around the time of its completion in 1975. ... The Janus laser as it appeared in 1975. ... The Long Path laser was an early high energy infrared laser at the Lawrence Livermore National Laboratory used to study inertial confinement fusion. ... Physicist Frank Rainer (inset), who was involved in laser research and development at LLNL since 1966, holds the target chamber seen at the center of the larger picture. ... Laser Mégajoule (LMJ) is an experimental inertial confinement fusion (ICF) device being built in France by the French nuclear science directorate, CEA. Laser Mégajoule plans to deliver about 1. ... GEKKO XII is a high-power 12-beam neodymium doped glass laser at the Osaka Universitys Institute for Laser Engineering completed in 1983, which is used for high energy density physics and inertial confinement fusion research. ... The ISKRA-4 and ISKRA-5 lasers are lasers which were built by the Russian federation at RFNC-VNIIEF in Arzamas-16() with the ~2Kj output ISKRA-4 laser being completed in 1979 and the ~30Kj output ISKRA-5 laser which was completed in 1989. ... Zork universe Zork games Zork Anthology Zork trilogy Zork I   Zork II   Zork III Beyond Zork   Zork Zero   Planetfall Enchanter trilogy Enchanter   Sorcerer   Spellbreaker Other games Wishbringer   Return to Zork Zork: Nemesis   Zork Grand Inquisitor Zork: The Undiscovered Underground Topics in Zork Encyclopedia Frobozzica Characters   Kings   Creatures Timeline   Magic   Calendar...


See also: International Fusion Materials Irradiation Facility The International Fusion Material Irradiation Facility, also known as IFMIF, is an international scientific research program designed to test materials for suitability for use in a fusion reactor. ...


 
 

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