Measurement of time constants for superconducting cables with Hall probes

Yanagi, N.; Takács, S.; Mito, T.; Takahata, K.; Iwamoto, A.; Yamamoto, Junya

doi:10.1016/s0011-2275(97)00099-4

Cited by 11 publications

(27 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The losses per cycle therefore decrease weaker at higher frequencies. Some measurements indicate this [21][22][23][24][25][26]. Our results are obtained by the analogy with the induced currents in normal metals.…”

Section: Commentssupporting

confidence: 58%

See 1 more Smart Citation

AC losses in superconductors shielded by a normal metal or another superconductor

Takács

2010

Supercond. Sci. Technol.

View full text Add to dashboard Cite

We investigate the flux penetration into the system of two (super-or normal conducting) regions when some of the regions are 'shielded' by the other one. The shield material may also consist of a normal conductor or superconductor. For simplicity, we consider this system in the slab geometry. The results indicate that shielding a superconducting cable by normal metal can decrease the total coupling losses. This effect surprisingly occurs already at frequencies much lower than the characteristic frequency corresponding to the maximum losses per cycle.

show abstract

Section: Commentssupporting

confidence: 58%

“…(b) We noticed also that the results differ from those when the normal layer is only on one side of the superconducting cable. In the latter case, there is a double peak in the frequency dependence of the losses per cycle [26]. We did not see any tendency for this effect in our case.…”

Section: Commentscontrasting

confidence: 41%

AC losses in superconductors shielded by a normal metal or another superconductor

Takács

2010

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…In this rapid rampdown process, the temperature of the conductor rises due to both AC losses and Joule losses in the normal zone. The AC loss power density is estimated by using the observed time constant of the screening currents between strands in the conductor [17]. The experimentally obtained resistivity of the stabilizer is used to give the temperature dependent Joule losses.…”

Section: Operation Of Helical Coil and Quench Protectionmentioning

confidence: 99%

Progress summary of LHD engineering design and construction

et al. 2000

View full text Add to dashboard Cite

In March 1998, the LHD project finally completed its eight year construction schedule. LHD is a superconducting (SC) heliotron type device with R = 3.9 m, ap = 0.6 m and B = 3 T, which has simple and continuous large helical coils. The major mission of LHD is to demonstrate the high potential of currentless helical-toroidal plasmas, which are free from current disruption and have an intrinsic potential for steady state operation. After intensive physics design studies in the 1980s, the necessary programmes of SC engineering R&D was carried out, and as a result, LHD fabrication technologies were successfully developed. In this process, a significant database on fusion engineering has been established. Achievements have been made in various areas, such as the technologies of SC conductor development, SC coil fabrication, liquid He and supercritical He cryogenics, development of low temperature structural materials and welding, operation and control, and power supply systems and related SC coil protection schemes. They are integrated, and nowadays comprise a major part of the LHD relevant fusion technology area. These issues correspond to the technological database necessary for the next step of future reactor designs. In addition, this database could be increased with successful commissioning tests just after the completion of the LHD machine assembly phase, which consisted of a vacuum leak test, an LHe cooldown test and a coil current excitation test. These LHD relevant engineering developments are recapitulated and highlighted. To summarize the construction of LHD as an SC device, the critical design with NbTi SC material has been successfully accomplished by these R&D activities, which enable a new regime of fusion experiments to be entered.

show abstract

“…where b is the cable width and c the layer thickness between the upper and lower strands. For other field directions, the inclusion of the corresponding demagnetization factor should be performed [20][21][22]. (Please note also the slightly different factors for flat cables in the papers cited above; the reasons for these differences are not always clear [23].)…”

Section: Introductionmentioning

confidence: 99%

Frequency dependence of coupling losses in twisted superconducting structures

Takács¹

2011

Supercond. Sci. Technol.

View full text Add to dashboard Cite

The coupling loss density per cycle in twisted structures (filaments in strands, strands in cables) is re-examined as a function of the frequency of the applied magnetic field. It is shown to be inversely proportional to the square root of the frequency in the high frequency limit, like the eddy current losses in normal metals. After attaining the maximum, this skin-effect type behaviour causes the decrease not to be as steep as for the calculations based on the simple model of the dipole mechanism for multifilamentary superconductors. The results are modified in a proper way to ensure easy comparison with the experiments, related to the maximum coupling losses per cycle and the characteristic frequency at which this maximum occurs.

show abstract

Measurement of time constants for superconducting cables with Hall probes

Cited by 11 publications

References 14 publications

AC losses in superconductors shielded by a normal metal or another superconductor

AC losses in superconductors shielded by a normal metal or another superconductor

Progress summary of LHD engineering design and construction

Frequency dependence of coupling losses in twisted superconducting structures

Contact Info

Product

Resources

About