Stefano Atzeni and JÜrgen Meyer-Ter-Vehn
- Published in print:
- 2004
- Published Online:
- January 2008
- ISBN:
- 9780198562641
- eISBN:
- 9780191714030
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198562641.003.0003
- Subject:
- Physics, Nuclear and Plasma Physics
The concept of inertial confinement fusion (ICF) is to burn a few milligrams of fuel compressed to more than 1000 times liquid density within the time interval in which mass inertia keeps the burning ...
More
The concept of inertial confinement fusion (ICF) is to burn a few milligrams of fuel compressed to more than 1000 times liquid density within the time interval in which mass inertia keeps the burning fuel together. The required densities can be obtained by imploding a spherical shell ‘target’ (or ‘capsule’) by high-power radiation (laser beams, ion beams, X-rays). Deposition of the beam energy leads to heating and ablation of the surface of the shell and generates the pressure that drives the implosion. The stages of shell implosion, ignition, and propagating burn are then essentially independent of the driver and the irradiation scheme. This chapter discusses the principles of inertial confinement fusion in a simple, almost self-contained manner, and illustrates them by 1-D simulation results of the implosion of a typical direct-drive laser-driven ICF target. Aspects of implosion symmetry are discussed and illustrated by 2-D simulations. The energy output of ICF reactor-size targets is also briefly described.Less
The concept of inertial confinement fusion (ICF) is to burn a few milligrams of fuel compressed to more than 1000 times liquid density within the time interval in which mass inertia keeps the burning fuel together. The required densities can be obtained by imploding a spherical shell ‘target’ (or ‘capsule’) by high-power radiation (laser beams, ion beams, X-rays). Deposition of the beam energy leads to heating and ablation of the surface of the shell and generates the pressure that drives the implosion. The stages of shell implosion, ignition, and propagating burn are then essentially independent of the driver and the irradiation scheme. This chapter discusses the principles of inertial confinement fusion in a simple, almost self-contained manner, and illustrates them by 1-D simulation results of the implosion of a typical direct-drive laser-driven ICF target. Aspects of implosion symmetry are discussed and illustrated by 2-D simulations. The energy output of ICF reactor-size targets is also briefly described.
Stefano Atzeni and JÜrgen Meyer-Ter-Vehn
- Published in print:
- 2004
- Published Online:
- January 2008
- ISBN:
- 9780198562641
- eISBN:
- 9780191714030
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198562641.003.0009
- Subject:
- Physics, Nuclear and Plasma Physics
Hohlraum targets are a special class of ICF targets, in which capsule ablation is driven by the thermal radiation inside a cavity, the so-called hohlraum. In this scheme, the laser or ion beams do ...
More
Hohlraum targets are a special class of ICF targets, in which capsule ablation is driven by the thermal radiation inside a cavity, the so-called hohlraum. In this scheme, the laser or ion beams do not drive the capsule directly, and one therefore calls it indirect drive. Expressions for X-ray conversion efficiency are derived for incident laser and ion beams. Radiation confinement inside the cavity is discussed in terms of the wall albedo, which measures the re-emission of absorbed radiation by the heated wall. The radiative transfer between the walls is treated approximately by means of the viewfactor method. Simple estimates are derived for the hohlraum temperature of the black-body radiation. Simulations of radiatively driven implosions are presented in the context of targets for ion beam fusion.Less
Hohlraum targets are a special class of ICF targets, in which capsule ablation is driven by the thermal radiation inside a cavity, the so-called hohlraum. In this scheme, the laser or ion beams do not drive the capsule directly, and one therefore calls it indirect drive. Expressions for X-ray conversion efficiency are derived for incident laser and ion beams. Radiation confinement inside the cavity is discussed in terms of the wall albedo, which measures the re-emission of absorbed radiation by the heated wall. The radiative transfer between the walls is treated approximately by means of the viewfactor method. Simple estimates are derived for the hohlraum temperature of the black-body radiation. Simulations of radiatively driven implosions are presented in the context of targets for ion beam fusion.
D. Harlan Wilson
- Published in print:
- 2017
- Published Online:
- May 2018
- ISBN:
- 9780252041433
- eISBN:
- 9780252050039
- Item type:
- book
- Publisher:
- University of Illinois Press
- DOI:
- 10.5622/illinois/9780252041433.001.0001
- Subject:
- Literature, 20th-century Literature and Modernism
This biocritical study of J. G. Ballard is the first book to account for the entire life and work of the eccentric, prolific SF author. Ballard began his career publishing short stories in SF ...
More
This biocritical study of J. G. Ballard is the first book to account for the entire life and work of the eccentric, prolific SF author. Ballard began his career publishing short stories in SF magazines. Rather than explore outer space, his fiction explores “inner space,” drawing on the aesthetics of Surrealism and Freudian psychoanalysis. In the 1960s, he became associated with the New Wave movement in SF, which eschewed the principles of pulp SF in favor of literary modernism. Ballard’s oeuvre maps the unfolding of the mediapocalypse from the dawn of the Space Age into the 21st century; pathologized by the technology of electronic media, his characters are chronically harrowed by an implosion of real and cinematic landscapes as they struggle to find agency from the “death of affect” incited by the forces of late capitalism. Some scholarship has tried to remove Ballard from SF, arguing that he abandoned the genre halfway through his career, especially after publishing the fictional autobiography Empire of the Sun. As this book avows, however, Ballard began as, and always remained, a SF writer.Less
This biocritical study of J. G. Ballard is the first book to account for the entire life and work of the eccentric, prolific SF author. Ballard began his career publishing short stories in SF magazines. Rather than explore outer space, his fiction explores “inner space,” drawing on the aesthetics of Surrealism and Freudian psychoanalysis. In the 1960s, he became associated with the New Wave movement in SF, which eschewed the principles of pulp SF in favor of literary modernism. Ballard’s oeuvre maps the unfolding of the mediapocalypse from the dawn of the Space Age into the 21st century; pathologized by the technology of electronic media, his characters are chronically harrowed by an implosion of real and cinematic landscapes as they struggle to find agency from the “death of affect” incited by the forces of late capitalism. Some scholarship has tried to remove Ballard from SF, arguing that he abandoned the genre halfway through his career, especially after publishing the fictional autobiography Empire of the Sun. As this book avows, however, Ballard began as, and always remained, a SF writer.
Colin F. Baxter
- Published in print:
- 2018
- Published Online:
- September 2018
- ISBN:
- 9780813175287
- eISBN:
- 9780813175294
- Item type:
- chapter
- Publisher:
- University Press of Kentucky
- DOI:
- 10.5810/kentucky/9780813175287.003.0012
- Subject:
- History, Military History
World War II ended with unexpected suddenness. The dropping of two atomic bombs appeared to make conventional explosives obsolete; however, RDX and Composition B played a critical role in creating ...
More
World War II ended with unexpected suddenness. The dropping of two atomic bombs appeared to make conventional explosives obsolete; however, RDX and Composition B played a critical role in creating the detonation shockwave that “squeezed” the plutonium core of the “Fat Man” bomb that was dropped on Nagasaki, Japan.Less
World War II ended with unexpected suddenness. The dropping of two atomic bombs appeared to make conventional explosives obsolete; however, RDX and Composition B played a critical role in creating the detonation shockwave that “squeezed” the plutonium core of the “Fat Man” bomb that was dropped on Nagasaki, Japan.
Steve Redhead
- Published in print:
- 2008
- Published Online:
- September 2012
- ISBN:
- 9780748627882
- eISBN:
- 9780748671182
- Item type:
- chapter
- Publisher:
- Edinburgh University Press
- DOI:
- 10.3366/edinburgh/9780748627882.003.0005
- Subject:
- Society and Culture, Media Studies
This chapter is an extract from Baudrillard’s Simulacra and Simulation, with an editorial overview
This chapter is an extract from Baudrillard’s Simulacra and Simulation, with an editorial overview
Philippe Rochat
- Published in print:
- 2021
- Published Online:
- December 2020
- ISBN:
- 9780190057657
- eISBN:
- 9780190057688
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780190057657.003.0007
- Subject:
- Psychology, Cognitive Psychology, Developmental Psychology
We live in well-separated moral spheres, typically well compartmentalized, but they can collapse. These spheres are delimited by context and people, each calling for different moral biases and codes. ...
More
We live in well-separated moral spheres, typically well compartmentalized, but they can collapse. These spheres are delimited by context and people, each calling for different moral biases and codes. We develop a remarkable ability to switch moral codes depending on people and circumstances, as exemplified by Hitler and his pet dog or Ariel Castro with his child and neighbors. However, collapse between these spheres may happen causing great anxieties and, in some instances, can be lethal. Moral code implosions due to such collapse are the main cause of guilt, a major conundrum of human psychology.Less
We live in well-separated moral spheres, typically well compartmentalized, but they can collapse. These spheres are delimited by context and people, each calling for different moral biases and codes. We develop a remarkable ability to switch moral codes depending on people and circumstances, as exemplified by Hitler and his pet dog or Ariel Castro with his child and neighbors. However, collapse between these spheres may happen causing great anxieties and, in some instances, can be lethal. Moral code implosions due to such collapse are the main cause of guilt, a major conundrum of human psychology.
Philippe Rochat
- Published in print:
- 2021
- Published Online:
- December 2020
- ISBN:
- 9780190057657
- eISBN:
- 9780190057688
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780190057657.003.0008
- Subject:
- Psychology, Cognitive Psychology, Developmental Psychology
The fictive story of John wearing multiple hats for one head and his sudden mental collapse is an illustration of what personhood might be, in particular the true nature of who we are as moral ...
More
The fictive story of John wearing multiple hats for one head and his sudden mental collapse is an illustration of what personhood might be, in particular the true nature of who we are as moral agents. The self as moral agent is a process, not a static thing. There is no objective moral agent in itself, just as there is no objective cloud in itself: there is just something revealed in transition. The self as moral agent is revealed in transition from code to code, sphere to sphere, like the cloud is revealed by the constant transition of air masses from gas to solid state.Less
The fictive story of John wearing multiple hats for one head and his sudden mental collapse is an illustration of what personhood might be, in particular the true nature of who we are as moral agents. The self as moral agent is a process, not a static thing. There is no objective moral agent in itself, just as there is no objective cloud in itself: there is just something revealed in transition. The self as moral agent is revealed in transition from code to code, sphere to sphere, like the cloud is revealed by the constant transition of air masses from gas to solid state.
Harold A. Feiveson
- Published in print:
- 2014
- Published Online:
- January 2015
- ISBN:
- 9780262027748
- eISBN:
- 9780262319188
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262027748.003.0002
- Subject:
- Political Science, Security Studies
Fissile materials can sustain a nuclear chain reaction and are used in weapons and as reactor fuels. This chapter explains the production and use of the most common fissile materials, highly enriched ...
More
Fissile materials can sustain a nuclear chain reaction and are used in weapons and as reactor fuels. This chapter explains the production and use of the most common fissile materials, highly enriched uranium and plutonium. The highly enriched uranium typically used in weapons is enriched to 90 percent or higher in the isotope uranium-235. Gaseous diffusion was used to produce most of the highly enriched uranium in the world, but has been replaced by gas centrifuge technology. Plutonium is produced from uranium in reactors and separated from spent nuclear fuel in a reprocessing plant. Plutonium of almost any isotopic composition, including that produced in civilian power reactors, is weapons usable. In the bomb that destroyed Hiroshima, a gun-type assembly was used to create a supercritical mass of highly enriched uranium able to sustain an explosive chain reaction, while the Nagasaki weapon used a plutonium implosion compression assembly. In modern thermonuclear weapons, an implosion fission “primary” ignites a fusion-fission “secondary.” Such weapons generally typically contain about 3?4 kilograms of plutonium and 15?25 kilograms of highly enriched uranium.Less
Fissile materials can sustain a nuclear chain reaction and are used in weapons and as reactor fuels. This chapter explains the production and use of the most common fissile materials, highly enriched uranium and plutonium. The highly enriched uranium typically used in weapons is enriched to 90 percent or higher in the isotope uranium-235. Gaseous diffusion was used to produce most of the highly enriched uranium in the world, but has been replaced by gas centrifuge technology. Plutonium is produced from uranium in reactors and separated from spent nuclear fuel in a reprocessing plant. Plutonium of almost any isotopic composition, including that produced in civilian power reactors, is weapons usable. In the bomb that destroyed Hiroshima, a gun-type assembly was used to create a supercritical mass of highly enriched uranium able to sustain an explosive chain reaction, while the Nagasaki weapon used a plutonium implosion compression assembly. In modern thermonuclear weapons, an implosion fission “primary” ignites a fusion-fission “secondary.” Such weapons generally typically contain about 3?4 kilograms of plutonium and 15?25 kilograms of highly enriched uranium.
Chris Bishop
- Published in print:
- 2016
- Published Online:
- May 2018
- ISBN:
- 9781496808509
- eISBN:
- 9781496808547
- Item type:
- chapter
- Publisher:
- University Press of Mississippi
- DOI:
- 10.14325/mississippi/9781496808509.003.0007
- Subject:
- Literature, Comics Studies
Failure can be just as illuminating as success, and so this looks at the alarmingly short-lived Beowulf: Dragon Slayer. By the mid-1970s, when the Anglo-Saxon hero appeared in his own title series, ...
More
Failure can be just as illuminating as success, and so this looks at the alarmingly short-lived Beowulf: Dragon Slayer. By the mid-1970s, when the Anglo-Saxon hero appeared in his own title series, Beowulf, the Anglo-Saxon poem, was yet to transition from an academic to a popular milieu, and a continuous and steadfastly nationalist interpretation made it very difficult for the poem’s eponymous hero to get the sort of traction enjoyed by folk heroes such as Robin Hood or Thor. Subsequently, Beowulf: Dragon Slayer, despite the innate worthiness of its subject and despite the efforts of DC heavyweights like Michael Uslan, was doomed before issue one hit the newsstands.Less
Failure can be just as illuminating as success, and so this looks at the alarmingly short-lived Beowulf: Dragon Slayer. By the mid-1970s, when the Anglo-Saxon hero appeared in his own title series, Beowulf, the Anglo-Saxon poem, was yet to transition from an academic to a popular milieu, and a continuous and steadfastly nationalist interpretation made it very difficult for the poem’s eponymous hero to get the sort of traction enjoyed by folk heroes such as Robin Hood or Thor. Subsequently, Beowulf: Dragon Slayer, despite the innate worthiness of its subject and despite the efforts of DC heavyweights like Michael Uslan, was doomed before issue one hit the newsstands.
Vladan Starcevic, MD, PhD
- Published in print:
- 2009
- Published Online:
- November 2020
- ISBN:
- 9780195369250
- eISBN:
- 9780197562642
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195369250.003.0009
- Subject:
- Clinical Medicine and Allied Health, Psychiatry
Specific phobias (also referred to as simple phobias and isolated phobias) represent a heterogeneous group of disorders characterized by excessive and/or irrational fear of one of relatively few ...
More
Specific phobias (also referred to as simple phobias and isolated phobias) represent a heterogeneous group of disorders characterized by excessive and/or irrational fear of one of relatively few and usually related objects, situations, places, phenomena, or activities (phobic stimuli). The phobic stimuli are either avoided or endured with intense anxiety or discomfort. People with specific phobias are aware that their fear is unreasonable, but this does not diminish the intensity of the fear. Rather, they are quite distressed about being afraid or feel handicapped by their phobia. Specific phobias are frequently encountered in the general population, but they are relatively uncommon in the clinical setting. Most phobias have a remarkable tendency to persist, prompting an assumption that they cannot be easily extinguished because of their ‘‘purpose’’ to protect against danger. Specific phobias are deceptively simple, as they are easy to describe and recognize but often difficult to understand. There are several conceptual problems and a number of issues associated with specific phobias:… 1. Where are the boundaries of specific phobias? How can we develop better criteria on the basis of which specific phobia could be distinguished as a psychiatric disorder from fears and avoidance considered to be within the realm of ‘‘normality?’’ 2. How can specific phobias be taken seriously by both the sufferers and clinicians? 3. In view of the considerable differences between various types of specific phobias, should they continue to be grouped together? 4. Should specific phobias be grouped on the basis of whether they are driven by fear or disgust? 5. In view of its unique features, should the blood-injection-injury type of specific phobia be given a separate psychopathological, diagnostic, and nosological status? 6. Considering a significant overlap between situational phobias and agoraphobia, should they be grouped together, along a hypothetical situational phobia/agoraphobia spectrum? 7. What is the relationship between specific phobias and other psychopathology? Are they relatively isolated from other disorders, both cross-sectionally and longitudinally, or should they more appropriately be conceptualized as a predisposition to or a risk factor for some psychiatric conditions? 8. How specific are pathways that lead to specific phobias? 9. Has the dominant treatment model for specific phobias, based on exposure therapy, exhausted its potential? Is the tendency for specific phobias to persist adequately addressed by treatments derived from learning theory?
Less
Specific phobias (also referred to as simple phobias and isolated phobias) represent a heterogeneous group of disorders characterized by excessive and/or irrational fear of one of relatively few and usually related objects, situations, places, phenomena, or activities (phobic stimuli). The phobic stimuli are either avoided or endured with intense anxiety or discomfort. People with specific phobias are aware that their fear is unreasonable, but this does not diminish the intensity of the fear. Rather, they are quite distressed about being afraid or feel handicapped by their phobia. Specific phobias are frequently encountered in the general population, but they are relatively uncommon in the clinical setting. Most phobias have a remarkable tendency to persist, prompting an assumption that they cannot be easily extinguished because of their ‘‘purpose’’ to protect against danger. Specific phobias are deceptively simple, as they are easy to describe and recognize but often difficult to understand. There are several conceptual problems and a number of issues associated with specific phobias:… 1. Where are the boundaries of specific phobias? How can we develop better criteria on the basis of which specific phobia could be distinguished as a psychiatric disorder from fears and avoidance considered to be within the realm of ‘‘normality?’’ 2. How can specific phobias be taken seriously by both the sufferers and clinicians? 3. In view of the considerable differences between various types of specific phobias, should they continue to be grouped together? 4. Should specific phobias be grouped on the basis of whether they are driven by fear or disgust? 5. In view of its unique features, should the blood-injection-injury type of specific phobia be given a separate psychopathological, diagnostic, and nosological status? 6. Considering a significant overlap between situational phobias and agoraphobia, should they be grouped together, along a hypothetical situational phobia/agoraphobia spectrum? 7. What is the relationship between specific phobias and other psychopathology? Are they relatively isolated from other disorders, both cross-sectionally and longitudinally, or should they more appropriately be conceptualized as a predisposition to or a risk factor for some psychiatric conditions? 8. How specific are pathways that lead to specific phobias? 9. Has the dominant treatment model for specific phobias, based on exposure therapy, exhausted its potential? Is the tendency for specific phobias to persist adequately addressed by treatments derived from learning theory?
Robert L. Devaney
Araceli Bonifant, Mikhail Lyubich, and Scott Sutherland (eds)
- Published in print:
- 2014
- Published Online:
- October 2017
- ISBN:
- 9780691159294
- eISBN:
- 9781400851317
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691159294.003.0008
- Subject:
- Mathematics, Combinatorics / Graph Theory / Discrete Mathematics
This chapter surveys dynamical properties of the families fsubscript c,𝜆(z) = zⁿ + c + λ/zᵈ for n ≥ 2, d ≥ 1, with c corresponding to the center of a hyperbolic component of the Multibrot set. These ...
More
This chapter surveys dynamical properties of the families fsubscript c,𝜆(z) = zⁿ + c + λ/zᵈ for n ≥ 2, d ≥ 1, with c corresponding to the center of a hyperbolic component of the Multibrot set. These rational maps produce a variety of interesting Julia sets, including Sierpinski carpets and Sierpinski gaskets, as well as laminations by Jordan curves. The chapter describes a curious “implosion” of the Julia sets as a polynomial psubscript c = zⁿ + c is perturbed to a rational map fsubscript c,𝜆. In this way the chapter shows yet another way of producing rational maps through “singular” perturbations of complex polynomials.Less
This chapter surveys dynamical properties of the families fsubscript c,𝜆(z) = zⁿ + c + λ/zᵈ for n ≥ 2, d ≥ 1, with c corresponding to the center of a hyperbolic component of the Multibrot set. These rational maps produce a variety of interesting Julia sets, including Sierpinski carpets and Sierpinski gaskets, as well as laminations by Jordan curves. The chapter describes a curious “implosion” of the Julia sets as a polynomial psubscript c = zⁿ + c is perturbed to a rational map fsubscript c,𝜆. In this way the chapter shows yet another way of producing rational maps through “singular” perturbations of complex polynomials.