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Argus was a two-beam high power infrared neodymium doped silica glass laser with a 20 cm (7.9 in) output aperture built at Lawrence Livermore National Laboratory in 1976 for the study of inertial confinement fusion. Argus advanced the study of laser-target interaction and paved the way for the construction of its successor, the 20 beam Shiva laser.

It was known from some of the earlier experiments in ICF that when large laser systems amplified their beams beyond a certain point (typically around the gigawatt level), nonlinear optical effects would begin to appear due to the very intense nature of the light. The most serious effect among these was "Kerr lensing", where, because the beam is so intense, that during its passage through either air or glass the electric field of the light actually alters the index of refraction of the material and causes the beam at the most intense points to "self focus" down to filament like structures of extremely high intensity. When a beam collapses into extremely high intensity filaments like this, it can easily exceed the optical damage threshold of laser glass and other optics, severely damaging them by creating pits, cracks and grey tracks through the glass. These effects became so severe after just the first few amplification stages of early lasers, that it was seen as essentially impossible to exceed the gigawatt level for ICF lasers without destroying the laser itself after just a few shots.

In order to improve the quality of the amplified beams, LLNL had started experimenting with the use of spatial filters in the single-beam Cyclops laser, built the previous year. The basic idea was to extend the laser device into a very long "beamline", over which any imperfections that accumulated in the beam would be successively removed after every amplification stage. A series of tubes with lenses on either end would focus the light down to a point (the focal point) where it would pass through a pinhole which would reject stray unfocused light, smoothing the beam and eliminating the high intensity spots which would have otherwise been further amplified causing damage to down-beam optics. The technique was so successful on Argus it was often referred to as being "the savior of laser ICF".

After the success of Cyclops in beam smoothing, the next step was to further increase the energy and power in the resulting beams. Argus used a series of five groups of amplifiers and spatial filters arranged along the beamlines, each one boosting power until it reached a total of about 1 kilojoule and 1-2 terawatts per beam. These intensities would have been impossible to achieve without the use of spatial filtering. Argus was designed primarily to characterize large laser beamlines and laser-target interactions, there was no attempt to actually achieve the fusion ignition state in the device as this was understood to be impossible at the energies Argus was capable of delivering. Argus however, was used to further explore higher yields of the so-called "exploding pusher" type targets and to develop x-ray diagnostic cameras to view the hot plasma in such targets, a technique crucial to characterization of target performance on later ICF lasers.

Argus was capable of producing a total of about 4 terawatts of power in short pulses of up to about 100 picoseconds, or about 2 terawatts of power in a longer 1 nanosecond pulse (~2 kilojoules) on a 100 micrometer diameter fusion fuel capsule target. It became the first laser to perform experiments using X-rays produced by irradiating a hohlraum. The reduced production of hard X-ray energy via the production of hot electrons while using frequency doubled and tripled laser light (as opposed to the infrared light directly produced by the laser itself) was first noticed on Argus. This technique would also be later validated in the direct drive mode (at both the LLE and Novette laser) and subsequently used to enhance laser energy to target plasma coupling efficiency in experiments on nearly all subsequent laser inertial confinement devices. Argus was shut down and dismantled in September 1981. Maximum fusion yield for target implosions on Argus was about 109 neutrons per shot.
See also

Laser
Lawrence Livermore National Laboratory
List of laser articles
List of laser types

External links

https://web.archive.org/web/20041109063036/http://www.llnl.gov/50science/lasers.html
http://www.osti.gov/bridge/servlets/purl/16710-UOC0xx/native/16710.pdf
http://adsabs.harvard.edu/abs/1978ApOpt..17..999S

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Lawrence Livermore National Laboratory
Facilities

Mirror Fusion Test Facility
Tandem Mirror Experiment National Atmospheric Release Advisory Center National Energy Research Scientific Computing Center National Ignition Facility

Supercomputers

ASC Purple ASCI Blue Pacific ASCI White Peloton Sierra

Products
Lasers

Argus Cyclops Janus Long path Nova Novette Shiva

Others

Gist LLNL RISE process LX-14 Micropower impulse radar Reliable Replacement Warhead ROSE SCALD Silo Slapper detonator W47 W70 W71 Yorick

People

Ernest Lawrence Edward Teller

Related

IBM Blue Gene Inertial confinement fusion Laser Inertial Fusion Energy Stockpile stewardship Sustained Spheromak Physics Experiment Z-Division

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Fusion power, processes and devices
Core topics

Nuclear fusion
Timeline List of experiments Nuclear power Nuclear reactor Atomic nucleus Fusion energy gain factor Lawson criterion Magnetohydrodynamics Neutron Plasma

Processes,
methods
Confinement
type
Gravitational

Alpha process Triple-alpha process CNO cycle Fusor Helium flash Nova
remnants Proton-proton chain Carbon-burning Lithium burning Neon-burning Oxygen-burning Silicon-burning R-process S-process

Magnetic

Dense plasma focus Field-reversed configuration Levitated dipole Magnetic mirror
Bumpy torus Reversed field pinch Spheromak Stellarator Tokamak
Spherical Z-pinch

Inertial

Bubble (acoustic) Laser-driven Magnetized Liner Inertial Fusion

Electrostatic

Fusor Polywell

Other forms

Colliding beam Magnetized target Migma Muon-catalyzed Pyroelectric

Devices, experiments
Magnetic confinement
Tokamak

International

ITER DEMO PROTO

Americas

Canada STOR-M United States Alcator C-Mod ARC
SPARC DIII-D Electric Tokamak LTX NSTX
PLT TFTR Pegasus Brazil ETE Mexico Novillo [es]

Asia,
Oceania

China CFETR EAST
HT-7 SUNIST India ADITYA SST-1 Japan JT-60 QUEST [ja] Pakistan GLAST South Korea KSTAR

Europe

European Union JET Czech Republic COMPASS GOLEM [cs] France TFR WEST Germany ASDEX Upgrade TEXTOR Italy FTU IGNITOR Portugal ISTTOK Russia T-15 Switzerland TCV United Kingdom MAST-U START STEP

Stellarator
Americas

United States CNT CTH HIDRA HSX Model C NCSX Costa Rica SCR-1

Asia,
Oceania

Australia H-1NF Japan Heliotron J LHD

Europe

Germany WEGA Wendelstein 7-AS Wendelstein 7-X Spain TJ-II Ukraine Uragan-2M
Uragan-3M [uk]

RFP

Italy RFX United States MST

Magnetized target

Canada SPECTOR United States LINUS FRX-L – FRCHX Fusion Engine

Other

Russia GDT United States Astron LDX Lockheed Martin CFR MFTF
TMX Perhapsatron PFRC Riggatron SSPX United Kingdom Sceptre Trisops ZETA

Inertial confinement
Laser
Americas

United States Argus Cyclops Janus LIFE Long path NIF Nike Nova OMEGA Shiva

Asia

Japan GEKKO XII

Europe

European Union HiPER Czech Republic Asterix IV (PALS) France LMJ LULI2000 Russia ISKRA United Kingdom Vulcan

Non-laser

United States PACER Z machine

Applications

Thermonuclear weapon
Pure fusion weapon

International Fusion Materials Irradiation Facility ITER Neutral Beam Test Facility

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Solid-state lasers
Distinct subtypes
Semiconductor laser
Yttrium aluminium garnet

Nd:YAG laser Er:YAG laser Nd:Cr:YAG Yb:YAG Nd:Ce:YAG Ho:YAG Dy:YAG Sm:YAG Tb:YAG Ce:YAG Ce:Gd:YAG Gd:YAG

Glass

Nd:glass Ytterbium glass 147Pm+3:Glass Er:Yb:Glass

Other gain media

Ruby laser Yttrium iron garnet (YIG) Terbium gallium garnet (TGG) Ti:sapphire laser Solid-state dye laser (SSDL/SSOL/SSDPL) Yttrium lithium fluoride (YLF)
Neodymium-doped yttrium lithium fluoride (Nd:YLF) Yttrium orthovanadate (YVO4)
Neodymium-doped yttrium orthovanadate (Nd:YVO4) Yttrium calcium oxoborate (YCOB)
Nd:YCOB laser Ce:LiSAF Ce:LiCAF Cr:ZnSe U:CaF2 Sm:CaF2 Yb:SFAP

Structures

Diode-pumped solid-state laser (DPSSL) Fiber laser Figure-8 laser Disk laser F-center laser

Specific lasers

Trident laser ZEUS-HLONS (HMMWV Laser Ordnance Neutralization System) Nova (laser) Cyclops laser Janus laser Argus laser Shiva laser HiPER Laboratory for Laser Energetics Laser Mégajoule LULI2000 Mercury laser ISKRA-6 Vulcan laser

Aspects

Mode-locking Energy transfer upconversion Solar-pumped laser

Laser types: Solid-state
Semiconductor Dye Gas
Chemical Excimer Ion Metal Vapor

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Lasers

List of laser articles List of laser types List of laser applications Laser acronyms

Laser types: Solid-state
Semiconductor Dye Gas
Chemical Excimer Ion Metal Vapor

Laser physics

Active laser medium Amplified spontaneous emission Continuous wave Doppler cooling Laser ablation Laser cooling Laser linewidth Lasing threshold Magneto-optical trap Optical tweezers Population inversion Resolved sideband cooling Ultrashort pulse

Laser optics

Beam expander Beam homogenizer B Integral Chirped pulse amplification Gain-switching Gaussian beam Injection seeder Laser beam profiler M squared Mode-locking Multiple-prism grating laser oscillator Multiphoton intrapulse interference phase scan Optical amplifier Optical cavity Optical isolator Output coupler Q-switching Regenerative amplification

Laser spectroscopy

Cavity ring-down spectroscopy Confocal laser scanning microscopy Laser-based angle-resolved photoemission spectroscopy Laser diffraction analysis Laser-induced breakdown spectroscopy Laser-induced fluorescence Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy Raman spectroscopy Second-harmonic imaging microscopy Terahertz time-domain spectroscopy Tunable diode laser absorption spectroscopy Two-photon excitation microscopy Ultrafast laser spectroscopy

Laser ionization

Above-threshold ionization Atmospheric-pressure laser ionization Matrix-assisted laser desorption/ionization Resonance-enhanced multiphoton ionization Soft laser desorption Surface-assisted laser desorption/ionization Surface-enhanced laser desorption/ionization

Laser fabrication

Laser beam welding Laser bonding Laser converting Laser cutting Laser cutting bridge Laser drilling Laser engraving Laser-hybrid welding Laser peening Multiphoton lithography Pulsed laser deposition Selective laser melting Selective laser sintering

Laser medicine

Computed tomography laser mammography Laser capture microdissection Laser hair removal Laser lithotripsy Laser coagulation Laser surgery Laser thermal keratoplasty LASIK Low-level laser therapy Optical coherence tomography Photorefractive keratectomy Photorejuvenation

Laser fusion

Argus laser Cyclops laser GEKKO XII HiPER ISKRA lasers Janus laser Laboratory for Laser Energetics Laser integration line Laser Mégajoule Long path laser LULI2000 Mercury laser National Ignition Facility Nike laser Nova (laser) Novette laser Shiva laser Trident laser Vulcan laser

Civil applications

3D laser scanner CD DVD Blu-ray Laser lighting display Laser pointer Laser printer Laser tag

Military applications

Advanced Tactical Laser Boeing Laser Avenger Dazzler (weapon) Electrolaser Laser designator Laser guidance Laser-guided bomb Laser guns Laser rangefinder Laser warning receiver Laser weapon LLM01 Multiple Integrated Laser Engagement System Tactical High Energy Laser Tactical light ZEUS-HLONS (HMMWV Laser Ordnance Neutralization System)

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Index

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