Pulse properties of large 50-50 NiFe tape cores

Winter, S.; Kuenning, R.W.; Berg, G.P.A.

doi:10.1109/tmag.1970.1066693

Cited by 28 publications

(11 citation statements)

References 1 publication

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“…Inspection of figures 1-3 reveals that at high switching rates and in the thicker material the drive field curve consists of four main regions: (i) an initial steep rise attributable to instrumental causes including stray inductance, (ii) a fairly level or gently falling 'step' region, (iii) an approximately linear rising sw (saturation wave) region, followed by (iv) the sharp final rise that signals the approach to saturation. These four regions are also clearly apparent in the drive field wave-forms reported by Winter et al (1970) that have already been briefly discussed by one of us (Bishop 1974). It is clear that the linear rise in section (iii) quite closely follows the broken straight line in figures 1 and 2.…”

Section: Discussionsupporting

confidence: 58%

A comparison of rapid surface and volume magnetization measurements on 50% NiFe tape with models of eddy-current-limited domain wall motion

Bishop

Williams

1977

J. Phys. D: Appl. Phys.

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Drive field characteristics during rapid (0.1-7 T mu s-1) constant-voltage magnetization reversals in HCR tapes of thickness 6, 12 and 25 mu m are reported. Four stages may be distinguished: (i) a sharp rise of instrumental origin, (ii) a fairly level 'step', (iii) a roughly linear rise that accords well with the 'saturation-wave' (SW) model, and (iv) a steep rise before saturation. Magneto-optic observation shows that the surface magnetization practically saturates at the step to SW transition. This occurs relatively earlier the faster the switch and the thicker the tape. Two models for the step stage are considered. In the first (BDM) bar domains are separated by walls that span the tape thickness. The second (SDM) consists of surface domains of roughly semi-elliptical cross-section. Both assume a detailed balance between domain wall surface tension and magnetic field pressure.

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Section: Discussionsupporting

confidence: 58%

A comparison of rapid surface and volume magnetization measurements on 50% NiFe tape with models of eddy-current-limited domain wall motion

Bishop

Williams

1977

J. Phys. D: Appl. Phys.

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“…Thus, a model with DELTAMAX cores, i.e. 50–50 NiFe25 was developed and tested. The typical parameters and test results are listed in Table 3 with its threshold voltage.…”

Section: Methodsmentioning

confidence: 99%

On the safety of ITER accelerators

2013

Sci Rep

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Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate −1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER.

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“…In these cases, thin SA1 and FT-1H and FT-2H, we arbitrar- ily assigned each value to a different line; the achieved interlaminar voltage is uncertain by that amount. A larger uncertainty arises if the core had a large ratio of inner to outer diameter, for which it has been shown that the radial voltage gradient initially peaks across the inner laminations until they saturate, then the peak voltage propagates outwards [32]. The peak interlaminar voltage may then be 2-3 times the average that we show in Table V.…”

Section: Coatingsmentioning

confidence: 72%

Induction core alloys for heavy-ion inertial fusion-energy accelerators

Molvik

Faltens

2002

Phys. Rev. ST Accel. Beams

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Induction core alloys are evaluated that are appropriate for heavy-ion induction accelerators to drive heavy-ion inertial fusion (HIF) power plants. Parameters evaluated include the usable flux swing and the energy loss over a range of magnetization rates of ϳ10 5 10 7 T͞s, corresponding to pulse durations of ϳ20 to 0.2 ms, respectively. The usable flux swing, for minimum core losses, extends from near the reversed remanent field to about 80% of the saturation field. The usable flux swing is enhanced, with little increase in losses, by annealing the core after winding. Maintaining low energy loss at high magnetization rates requires insulation to block interlaminar eddy currents. To obtain annealed cores with a high ratio of remanent to saturation magnetic field, the insulation must withstand annealing temperatures and apply minimum mechanical stress to the core during cooldown. We find that commercially available insulating coatings for amorphous metals either break down near 10 6 T͞s (a factor of 10 below the requirement), or do not achieve the maximum remanent field and hence the usable flux swing after annealing. More satisfactory coatings are available for silicon steel and nanocrystalline alloys, which could have applications in HIF. Amorphous alloys are capable of meeting most HIF needs, especially with improved coatings.

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Pulse properties of large 50-50 NiFe tape cores

Cited by 28 publications

References 1 publication

A comparison of rapid surface and volume magnetization measurements on 50% NiFe tape with models of eddy-current-limited domain wall motion

A comparison of rapid surface and volume magnetization measurements on 50% NiFe tape with models of eddy-current-limited domain wall motion

On the safety of ITER accelerators

Induction core alloys for heavy-ion inertial fusion-energy accelerators

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