Classification of disruptions in PBX

Itami, K.; Jahns, G.L.; Yamada, Hitoshi; McGuire, K.

doi:10.2172/5139742

Cited by 5 publications

(9 citation statements)

References 6 publications

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“…In particular, we will present data typifying two different disruption scenarios, one with the disruption immediately following the rapid growth of a low m/n precursor mode, and one which exhibits distinct phases: growth and 'crash' of the precursor mode, a delay period of several milliseconds following the crash, and then the disruption. The observation of sawtooth-like crashes that could cause a large and rapid energy loss from the plasma was reported previously [7,8], and in the latter paper it was recognized that crashes with large enough energy loss (> 20%) inevitably led to a disruptive termination of the discharge. Following the presentation of the disruption scenarios, we will present a statistical picture of the dependence of some of the identifiable disruption parameters on discharge characteristics.…”

Section: Introductionmentioning

confidence: 59%

Characteristics of low-q disruptions in PBX

Kaye¹,

Jahns²,

Morris³

et al. 1988

Nucl. Fusion

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At low q^ (2.3 < q^ < 4.5), in the Princeton Beta Experiment, the discharges are limited by a hard disruption following the growth and sawtooth-like 'crash' of a <25 kHz precursor oscillation. The disruption, which occurs even in discharges with <)3 t > well below the first stability regime boundary (=2.5 /XoI p /aB t), follows the crash of this precursor mode either immediately or with a delay of several milliseconds, with the immediate disruptions primarily occurring in the discharges with (0 t > close to the first regime limit. The highest limiting process. The delay period is interpreted as a period during which a locked mode, consisting of several toroidal components of comparable amplitude, grows. Because of the energy loss associated with the crash, the plasma goes vertically unstable during the delay period. The results of this study indicate that even within the relatively narrow low-q^ operating space, there is a continuum in the characteristics of the low-q^ disruptions with a primary dependence on the value of . While the ideal external kink instability may give rise to the growing oscillations that lead up to the ultimate disruption, the instabilities are weighted towards the edge only at the lowest q^, (<3) and highest . The results of this study indicate that effects outside the scope of ideal MHD theory may play a significant role in low-q^ disruptions.

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Section: Introductionmentioning

confidence: 59%

Characteristics of low-q disruptions in PBX

Kaye¹,

Jahns²,

Morris³

et al. 1988

Nucl. Fusion

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“…It is aiso possible, as speculated in Ref. [8], that slight inward radial excursions due to large sawtooth oscillations at high beta, high indentation operation will be sufficient to cause the plasma to lose axisymmetric stability.…”

Section: Discussionmentioning

confidence: 96%

“…The coil locations are indicated in the figure and described further in Ref. [8]. We note here that coils 8, 13, 15 are in the same poloidal location but are rotated toroidally 120* from each other, and similarly for coils 2, 16.…”

Section: B Axisymmetric Instabilitymentioning

confidence: 86%

Post-disruptive plasma loss in the Princeton Beta Experiment (PBX)

Jardin¹,

DeLucia²,

Okabayashi³

et al. 1986

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The free-boundary, ?xisymmetric tokamak simulation code TSC is used to model the transport time scale evolution and positional stability of PB.X. A disruptive thermal quench i-'ill cause the plasma column to move inward in major radius. It is shown that the plasma can then lose axisymmetric stability, causing it to displace exponentially off the raidplane, terminating the discharge. We verify the accuracy of the code by modeling several controlled experimental shots in PBX. DISCLAIMERThis report was prepared as an account of work sponsored by an agency o] the United States Government. Neither the United Slates Government nor any agency tnereor, nor any of their irniployecs, makes any warranty, express or implied, or assumes any legal liability or responsi bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owne^ rights. Refer ence herein to any specific commercial product, process, or servir-c by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom mendation, or favoring by the United Stales Government or any agency thenajf. The views and opinions or authors expressed herein do nol necessarily state or reflect those of the Unir-jd States Government or any ape^ey thereof.

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“…"[ Note 3] Itami used words as well as architectural works to actively express his theories to society. He wrote numerous books, with five collections of his writings published in Japan [3][4][5][6][7] and nine books on Joseon, [8][9][10][11][12][13][14][15][16] as well as texts on interiors, dwellings, and architectural drawings [17][18][19] totaling 17 volumes. In addition, a collection of his discourse to date was published in 2004 20 in South Korea, whereas related books 21,22 were also issued for a retrospective exhibition after his death.…”

Section: Introduction: Research Background Objectives Targets and Met...mentioning

confidence: 99%

“…The writings studied here are those created by Itami to convey what he wanted to express through words. Specifically, they comprise all materials available in his writings published in books, including collections, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] special magazine editions, 30 books containing dialogue transcriptions, 31 submissions to magazines, 32,33 and exegeses of his work. [Note 4] Thus, a total of 108 writings were collected, with 472 discourse themes extracted and structured[Note 5]; the writings discussed here are presented in Table 1[ Note 6] and examples of the extracted items are shown in Table 2.…”

Section: Introduction: Research Background Objectives Targets and Met...mentioning

confidence: 99%