What are the contributions mentioned in the paper "Dynamic resistance measurements in a gdbco- coated conductor" ?

Here, the authors present dynamic resistance measurements of a 5 mm-wide Fujikura coated conductor wire at 77 K. The authors report experimental values obtain through varying the field angle ( the angle between magnetic field and normal vector of the conductor wide-face ), the DC current levels, and the magnetic field amplitude, and frequency. The authors show that the dynamic resistance in perpendicular magnetic field can be predicted using a simple analytical equation. The authors also show that, across the range of field angles measured here the dynamic resistance is dominated by the perpendicular component of the applied magnetic field.

What is the effect of the flow loss on the sample?

Flux flow loss leads to a rapid increase in totaldissipated power with increasing field amplitude, and the authors burnt out a sample during the measurement at It/Ic0 = 0.9 and high Ba due to this effect.

Why is the value of the threshold magnetic field given in Fig. 3?

The authors believe this is due to flux flow loss which occurs as the Ic(B) of the wire at the peak applied field falls below the magnitude of the total driven DCcurrent [15].

What are the possible causes of the dc/ic0 discrepancy?

There are several possible causes for this discrepancy, including: possible non-uniform Jc distributions in the sample wire; possible contributions due to Jc-B dependence of the wire; or possible errors in measured Ic0 values and GDBCO film dimensions used in the theoretical calculations.

(Open Access) Dynamic Resistance Measurements in a GdBCO-Coated Conductor (2017) | Zhenan Jiang

Q: What is the amplitude of the applied magnetic field?

It is the DC transport current, f is the frequency of the applied magnetic field, L is the distance between the two voltage taps.

Q: What is the maximum of the curve?

The maxima of this curve can be obtained from straightforward numerical methods to yield [15],(3)where Jc0 is defined as Ic0/(2a × 2t).

Q: What was the purpose of the experiment?

Two sets of voltage taps were prepared as seen in Fig. 2(b): in the first set, two voltage taps were attached on the center of the sample, and two voltage signal wires run opposite along the sample axis and meet in the center of the sample; in the second set, a spiral loop was arranged around the sample as shown in the figure [17].

Q: How does the dynamic resistance of a GaBCO coated conductor be determined?

The authors have measured dynamic resistance in a 5 mm-wide Fujikura GaBCO coated conductor at 77 K when exposed to ACexternal magnetic fields at various applied field angles and amplitudes up to 100 mT.

Q: How many times did the authors measure Bth?

The authors have obtained experimental values for Bth, ⊥ from the x-axis intercept of linear fits of the composite datasetusing all frequencies measured for each value of It/Ic0.

Q: What is the effect of the high aspect ratio of the coated conductor wire?

This is a result of the very high aspect ratio of the coated conductor wire, which ensures that shieldingcurrents are restricted to flow only within the ~ 2.3 m GdBCO film.

> ASC2016-4MPo2E-11<

Dynamic resistance measurements in a GdBCO-

coated conductor

Zhenan Jiang, Ryuki Toyomoto, Naoyuki Amemiya, Chris W. Bumby, Rodney A. Badcock, Nicholas J. Long

Abstract— Dynamic resistance is a phenomenon which occurs

when a superconducting wire carries DC transport current whilst

experiencing an alternating magnetic field. This situation occurs

in a range of HTS machinery applications, where dynamic

resistance can lead to large parasitic heat loads and potential

quench events. Here, we present dynamic resistance

measurements of a 5 mm-wide Fujikura coated conductor wire at

77 K. We report experimental values obtain through varying the

field angle (the angle between magnetic field and normal vector of

the conductor wide-face), the DC current levels, and the magnetic

field amplitude, and frequency. We show that the dynamic

resistance in perpendicular magnetic field can be predicted using

a simple analytical equation. We also show that, across the range

of field angles measured here the dynamic resistance is dominated

by the perpendicular component of the applied magnetic field.

Index Terms— Dynamic resistance, ReBCO, GdBCO, coated

conductor.

I. INTRODUCTION

ynamic resistance occurs when a superconducting wire

carries DC transport current whilst experiencing an

alternating magnetic field [1, 2]. In HTS applications such as

rotating machines, magnets, and SMES (Superconducting

Energy Storage Systems), dynamic resistance plays an

important role [3-6]. In HTS flux pumps, dynamic resistance

within the HTS stator determines the maximum available

output current [7-11]. In recent years, HTS coated conductors

have become the dominant wire choice for next generation

superconducting machines [12], and hence accurate prediction

of the dynamic resistance incurred within an HTS coated

conductor wire is a critical issue.

Oomen et al developed an analytical model for calculating

dynamic resistance in a superconducting slab in an AC parallel

magnetic field [2]. There have been some previous

experimental reports on dynamic resistance in coated

conductors in AC perpendicular magnetic fields [13, 14].

However, this previous work has only employed applied

magnetic field amplitudes of < 20 mT, and the wire I

value for

the measurements reported in [13] was much smaller than

today’s wires.

Recently we have measured the dynamic resistance in a 4

mm-wide SuperPower coated conductor in AC perpendicular

magnetic field up to 100 mT, and have developed an equation

Manuscript submitted September 02, 2016. This work was partially

supported by the JSPS (Japan Society for the Promotion of Science).

Zhenan Jiang, Chris W. Bumby, Rodney A. Badcock, and Nicholas J. Long

are with the Robinson Research Institute, Victoria University of Wellington,

PO Box 33436, Lower Hutt 5046, New Zealand. (e-mail:

zhenan.jiang@vuw.ac.nz).

which can predict dynamic resistance in a superconducting strip

in perpendicular magnetic field. This approach employs a

formula adapted from the Oomen equation for a

superconducting slab in parallel magnetic fields [15].

Here, we present dynamic resistance measurement results in

a 5 mm-wide Fujikura GdBCO coated conductor at 77 K. This

Fujikura wire has a considerably higher self-field I

than the 4

mm-wide SuperPower wire previously reported, and hence

provides a test of the useful applicability of our developed

equation. In addition, in this work we examine the dependence

of dynamic resistance on the applied field angle (the angle

between magnetic field and normal vector of the conductor

wide-face,



, see Fig. 1).

FIG. 1 HERE

II. EXPERIMENTAL METHOD

Fig. 2(a) shows the experimental set-up used to make our

dynamic resistance measurements at 77 K [16]. The AC magnet

can generate up to 100 mT peak magnetic field at frequencies

up to 112.5 Hz. The sample can be rotated inside the magnet,

and the field angle,



can be varied from 0° to 360°. A 300 A

DC power supply was used to supply DC current to the 15 cm-

long Fujikura sample wire (FYSC-SC05). The sample was

fabricated by IBAD/PLD method, and has a self-field I

266.0 A at the 1 V/cm criterion, 77 K. The specification of the

sample is shown in Table 1. The DC circuit was arranged in

order to reduce coupling with the AC magnet circuit. Fig. 2(b)

shows voltage taps attached on the sample. Two sets of voltage

taps were prepared as seen in Fig. 2(b): in the first set, two

voltage taps were attached on the center of the sample, and two

voltage signal wires run opposite along the sample axis and

meet in the center of the sample; in the second set, a spiral loop

was arranged around the sample as shown in the figure [17].

The spiral loop was introduced to cancel out the effect from

external magnetic field. The distance between the voltage-taps

is 5 cm. The voltage output from the voltage taps were

measured using a Keithley 2182 nano-voltage meter.

Appropriate filters were used to average the voltage from the

voltage taps [18]. Dynamic resistance values measured from the

two voltage pick-ups were exactly the same, and the first set of

Ryuki Toyomoto and Naoyuki Amemiya are with Graduate School of

Engineering, Kyoto University, Kyoto, Kyoto-Daigaku-Katsura, Nishikyo,

Kyoto 615-8510, Japan.

> ASC2016-4MPo2E-11<

voltage taps was used in this work.

FIG. 2 HERE

TABLE 1 HERE

III. EQUATION FOR DYNAMIC RESISTANCE IN A STRIP IN

PERPENDICULAR MAGNETIC FIELD

The dynamic resistance per unit length per cycle in a

superconducting strip, carrying DC current exposed to AC

perpendicular magnetic field, R

⊥

, can be estimated using the

following equation [15],

(1)

where a is half-width of the coated conductor, B

⊥

is the

amplitude of applied magnetic field, I

(266.0 A) is the self-

field critical current of the conductor, I

is the DC transport

current, f is the frequency of the applied magnetic field, L is the

distance between the two voltage taps. The threshold magnetic

field, B

th,

⊥

is given by,

(2)

where (1- I

) is the DC current filling factor and B

⊥

effective penetration field [19, 20], which can be evaluated by

finding B

value at the maxima of the



curve shown in Fig. 3.

In this figure



= Q

, where Q

is the Brandt expression

for the theoretical magnetization loss in a superconducting

strip exposed to AC perpendicular magnetic field [21]. The

maxima of this curve can be obtained from straightforward

numerical methods to yield [15],

(3)

where J

is defined as I

/(2a × 2t). For the wire considered

here, we calculate that B

⊥

=51.71 mT, as shown in Fig. 3.

FIG. 3 HERE

IV. EXPERIMENTAL RESULTS

Fig. 4 shows the measured R

⊥

data obtained from the

sample at 3 different frequencies and 4 different values of the

reduced current, I

. In these plots R

⊥

is normalized by f. The

⊥

data for different frequencies show close agreement, which

indicates the hysteretic nature of the dynamic loss mechanism.

In all plots, R

⊥

is zero until the threshold magnetic field, B

th,

⊥

, is exceeded. We have obtained experimental values for B

th,

⊥

from the x-axis intercept of linear fits of the composite dataset

using all frequencies measured for each value of I

. B

th,

⊥

values decrease as the reduced current, I

is increased which

is consistent with Eq. (2). In Fig. 4(d), the R

⊥

data for f = 26.62

Hz deviate from the linear fit. We believe this is due to flux

flow loss which occurs as the I

(B) of the wire at the peak

applied field falls below the magnitude of the total driven DC

current [15]. Flux flow loss leads to a rapid increase in total

dissipated power with increasing field amplitude, and we burnt

out a sample during the measurement at I

= 0.9 and high B

due to this effect.

FIG. 4 HERE

The experimentally derived values of B

th,

⊥

from the Fujikura

sample are shown in Fig. 5(a) alongside calculated values based

on Eq. (2) [15]. The figure also shows calculated values

obtained using an alternative formula proposed by Ciszek et al,

which uses B

values in parallel fields in conjunction with a

calculated demagnetization factor [13]. It can be seen that the

experimentally obtained values of B

th,

⊥

have excellent

agreement with the values determined using Eq. (2), while the

Ciszek model only converges with our model and experiment

at high I

values.

Fig. 5(b) compares the gradient of the linear fits (dR

/dB

) in

Fig. 4 and the theoretical value of 4a/I

expected from Eq. (1).

This is plotted as a function of the reduced current I

. In all

cases the experimentally obtained gradient is larger than the

theoretical value, although agreement improves slightly with

increasing I

. The difference ranges between 30 – 15 %.

There are several possible causes for this discrepancy,

including: possible non-uniform J

distributions in the sample

wire; possible contributions due to J

-B dependence of the wire;

or possible errors in measured I

values and GDBCO film

dimensions used in the theoretical calculations.

In Fig. 6, R

data is plotted for measurements made at 3

different field angles,



= 0, 30, 60 , using 3 different I

values at 26.62 Hz. For a given I

, B

increases with

increasing field angle



while the gradient of the fitted linear

lines, dR

/dB

, and decreases with increasing field angle



These results can be explained by the fact that calculated

dynamic resistance in parallel magnetic field [2] is negligible

compared to our experimental results. For example, if we

consider B

= 100 mT, I

= 0.3 and f = 26.62 Hz, we find that

the experimentally measured R



= 60 is 1.19 /m/Hz.

This can be compared with a calculated value for the expected

dynamic resistance in parallel field of from the Oomen model

of 𝑅

d, ∥

= 5.76 x 10

-4

/m/Hz which is a factor of about 2000

smaller than the measured value. Fig. 7 shows calculated values

of 𝑅

d, ∥

for parallel field amplitudes up to 100 mT, and it is clear

that 𝑅

d, ∥

≪ 𝑅

throughout the experimental range reported

here. In light of this observation, it is reasonable to consider

whether the angular dependence of R

(α) can be explained

simply by the perpendicular component of B

which varies

according to B

cosα. Fig. 8 shows plots of B

cosα versus R



= 0, 30, 60. It is readily apparent that this simple

transformation leads to the data collapsing onto an

approximately common curve for all angles.

FIG. 6 HERE

FIG. 7 HERE

The apparent perpendicular threshold field, B

th,

⊥

(given by

( )

⊥⊥

⊥

−=

th, a,













−=

⊥⊥

p, th,



/9284.4

c00 p,

tJB =

⊥

> ASC2016-4MPo2E-11<

the x-axis intercept) now closely agree for the datasets collected

at each field angle. This is a result of the very high aspect ratio

of the coated conductor wire, which ensures that shielding

currents are restricted to flow only within the ~ 2.3 m GdBCO

film. This gives rise to a magnetization field which is always

perpendicular to the tape, and hence shields only the

perpendicular component of the applied field. This situation is

markedly different to that previously observed for BSCCO wire

[18], where the aspect ratio of the filamentary zone is normally

more than 100 times the aspect ratio (2a/2t) of a ReBCO wire.

FIG. 8 HERE

Fig. 8 also shows that the gradient dR

/dB

⊥

is also

approximately constant at



= 0, 30 and 60, although the

agreement at the largest field angle studied is not perfect, and

suggests the emergence of a further small contributing factor.

Nonetheless, Figure 8 provides strong evidence that R

(α)

the GdBCO coated conductor wire can be well described by

considering solely the contribution of the perpendicular field

component to Eq. (1).

V. CONCLUSION

We have measured dynamic resistance in a 5 mm-wide

Fujikura GaBCO coated conductor at 77 K when exposed to AC

external magnetic fields at various applied field angles and

amplitudes up to 100 mT.

The threshold field, B

th,

⊥

of the coated conductor in

perpendicular field can be accurately predicted from the

penetration field, B

⊥

identified from the maxima of the Brandt

gamma curve, and the DC current filling factor (1- I

). The

measured dynamic resistance, R

⊥

values in perpendicular

magnetic field, have reasonable agreement with the values

predicted from the Oomen equation for a superconducting slab

using the B

th,

⊥

values.

We have also shown that the dynamic resistance due to an a

magnetic field applied at angles up to 60 degrees from the

perpendicular field, can be accurately determined by

considering solely the contribution due to the perpendicular

field component. This situation is contrary to that previously

reported for BSCCO wire, and arises due to the very high aspect

ratio of the coated conductor wire, which restricts shielding

currents to flow solely in the plane of the ReBCO film.

ACKNOWLEDGMENT

The authors acknowledge Drs. N. Strickland and S. Wimbush

for I

(B,



) measurements of the sample at 77 K.

REFERENCES

[1] K. Ogasawara, K. Yasukochi, S. Nose, and H. Sekizawa, “Effective

resistance of current-carrying superconducting wire in oscillating

magnetic fields 1: Single core composite conductor,” Cryoginics, vol. 16,

pp. 33-38, Jan. 1976.

[2] M. P. Oomen, J. Rieger, M. Leghissa, B. ten Haken, and H. H. J. ten Kate,

“Dynamic resistance in a slab-like superconductor with J

(B)

dependence,” Supercond. Sci. Technol., vol. 12, pp. 382-387, 1999.

[3] S. S. Kalsi, Applications of high temperature superconductors to electric

power equipment (IEEE Press, New Jersey, 2011) pp.96.

[4] P. J. Masson, D. S. Soban, E. Upton, J. E. Pienkos, and C. A. Luongo,

“HTS motors in aircraft propulsion: design considerations”, IEEE Trans.

Appl. Supercond. vol. 15, pp. 2218 - 2221, 2005.

[5] P. N. Barnes, M. D. Sumption, and G. L. Rhoads, “Review of high power

density superconducting generators: Present state and prospects for

incorporating YBCO windings”, Cryogenics vol. 45, pp. 670-686, 2005.

[6] E. Pardo, “Modeling of AC loss in coils made of thin tapes under DC bias

current”, IEEE Trans. Appl. Supercond. vol. 24, 2013, Art. ID 4700105.

[7] Z. Jiang, K. Hamilton, N. Amemiya, R. A. Badcock, and C. W. Bumby,

“Dynamic resistance of a high-T

superconducting flux pump,” Appl.

Phys. Lett, vol. 105, Sep. 2014, Art. ID 112601.

[8] Z. Jiang, C. W. Bumby, R. A. Badcock, H. J. Sung, N. J. Long, and N.

Amemiya, “Impact of flux gap upon dynamic resistance of a rotating HTS

flux pump,” Supercond. Sci. Technol., vol. 28, Sep. 2015, Art. ID 115008.

[9] J. Geng and T. A. Coombs, “Mechanism of a high-Tc superconducting

flux pump: Using alternating magnetic field to trigger flux flow”, Appl.

Phys. Lett. vol. 107, 2015, Art. ID 142601.

[10] C. W. Bumby, Z. Jiang, J. G. Storey, A. E. Pantoja, R. A. Badcock,

“Anomalous open-circuit voltage from a high-T

superconductor

dynamo”, Appl. Phys. Lett. vol. 108, 2016, Art. ID 122601.

[11] C. W. Bumby, R. A. Badcock, H. J. Sung, K. M. Kim, Z. Jiang, A. E.

Pantoja, P. Bernado, M. Park, and R. G. Buckley, “Development of a

brushless HTS exciter for a 10 kW HTS synchronous generator”,

Supercond. Sci. Technol. vol. 29, 2016, Art. ID 024008.

[12] V. Selvamanickam, A. Guevara, Y. Zhang, I. Kesgin, Y. Xie, G. Carota,

Y. Chen, J. Dackow, Y. Zhang, Y. Zuev, C. Cantoni, A. Goyal, J. Coulter,

and L. Civale, “Enhanced and uniform in-field performance in long (Gd,

Y)–Ba–Cu–O tapes with zirconium doping fabricated by metal–organic

chemical vapor deposition” Supercond. Sci. Technol. vol. 23, 2010, Art.

ID 014014.

[13] M. Ciszek, O. Tsukamoto, J. Ogawa, and D. Miyagi, “Energy losses in

YBCO-123 coated conductors carrying transport current in perpendicular

external magnetic field”, AIP Conf. Proc. vol. 614, pp. 606-613, 2002.

[14] R. C. Duckworth, Y. F. Zhang, T. Ha, and M. J. Gouge “Dynamic

resistance of YBCO-coated conductors in applied AC fields with DC

transport currents and DC background fields,” IEEE Trans. Appl.

Supercond., vol. 21, pp. 3251-3256, June 2011.

[15] Z. Jiang, R. Toyomoto, N. Amemiya, X. Zhang, and C. W. Bumby,

“Dynamic resistance of a high-T

superconducting strip in perpendicular

magnetic field at 77 K”, 2016 In Press, Supercond. Sci. Technol.,

https://doi.org/10.1088/1361-6668/aa54e5

[16] Z. Jiang and N. Amemiya, “An experimental method for total AC loss

measurement of high T

superconductors”, Supercond. Sci. Technol. vol.

17, pp. 371- 379, 2004.

[17] S. Fukui, Y. Kitoh, T. Numata, O. Tsukamoto, J. Fujikami, and K.

Hayashi, “Transport current AC losses of high-Tc superconducting tapes

exposed to AC magnetic field”, Advances in Cryogenic Engineering, vol.

44, pp. 723-730, 1998.

[18] M. Ciszek, H. G. Knoopers, J. J. Rabbers, B. ten Haken, and H. H. J. ten

Kate, “Angular dependence of the dynamic resistance and its relation to

the AC transport current loss in Bi-2223/Ag tape superconductors”

Supercond. Sci. Technol. vol. 15, pp. 1275- 1280, 2002.

[19] M. Iwakuma, K. Toyota, M. Nigo, T. Kiss, K. Funaki, Y. Iijima, T. Saitoh,

Y. Yamada, and Y. Shiohara, “AC loss properties of YBCO

superconducting tapes fabricated by IBAD-PLD technique,” Physica C,

vol. 412-414, pp. 983-991, May 2004.

[20] A. Palau, T. Puig, X. Obradors, E. Pardo, C. Navau, A. Sanchez, A.

Usoskin, H. C. Freyhardt, L. Fernández, B. Holzapfel, and R. Feenstra,

“Simultaneous inductive determination of grain and intergrain critical

current densities of YBa

7-x

coated conductors”, Appl. Phys. Lett.

vol. 84, pp. 230 - 232, 2004.

[21] E. H. Brandt and M. Indenbom, “Type-II-superconductor strip with

current in a perpendicular magnetic field,” Phys. Rew. B, vol. 48, pp.

12893-12906, Nov. 1993.

TABLE I

SAMPLE SPECIFICATIONS

Critical current at self-field, 77 K (A)

266

Width of conductor (mm)

5.07

Ag layer (m)

6.4

Thickness of YBCO layer

(m)

2.3

Sample length (mm)

150

Thickness of substrate (m)

100

Thickness of stabilizing layer (m)

100

> ASC2016-4MPo2E-11<

Fig. 1. Definition of field angle .

Fig. 2. (a) Experimental set-up for dynamic resistance measurement, (b)

voltage tap arrangement.

Fig. 3.



plot of calculated AC magnetization loss [21],



= Q

used to

define the effective penetration field, B

in the sample. The maxima of



plot

occurs when B

= B

, which in this work is found to be 51.71 mT.

Fig. 4. Measured dynamic resistance values for different frequencies plotted as

a function of the amplitude of the applied magnetic field (a) I

= 0.1, (b) I

= 0.3, (c) I

= 0.5, (d) I

= 0.7.

Fig. 5. (a) Threshold magnetic field in perpendicular magnetic field, B

th, ⊥

, vs.

reduced current [15], (b) the gradient of the linear fits, dR

/dB

vs. 4a/I

from

Eq. (1).

Sample

Current lead

Rotation

DC power

supply

(a)

-2

-1

1 10 100

AC loss (Jm

-1

cycle

-1

-2

)

Perpendicular magnetic field (mT)

51.71 mT

0 20 40 60 80 100

26.62 Hz

65.44 Hz

112.5 Hz

Fit

d, ⊥

(/m/Hz)

a, ⊥

(mT)

= 0.1

(a)

0 20 40 60 80 100

= 0.3

(b)

d, ⊥

(/m/Hz)

a, ⊥

(mT)

0 20 40 60 80 100

= 0.5

(c)

d, ⊥

(/m/Hz)

a, ⊥

(mT)

0 20 40 60 80 100

= 0.7

(d)

d, ⊥

(/m/Hz)

a, ⊥

(mT)

0 0.2 0.4 0.6 0.8

Exp.

Eq. (2)

Ref. 13

th, ⊥

(mT)

(a)

0.05

0.1

0 0.2 0.4 0.6 0.8

4a/I

(/m/Hz/mT)

Eq. (1)

(b)

> ASC2016-4MPo2E-11<

Fig. 6. Measured dynamic resistance in various field angles at 26.62 Hz, (a)

/Ic

= 0.3, (b) I

/Ic

= 0.5, (c) I

/Ic

= 0.7.

Fig. 7. Calculated dynamic resistance due to parallel magnetic field, B

a, //

Fig. 8. Dynamic resistance in different field angles at 26.62 Hz, (a) I

/Ic

= 0.1,

(b) I

/Ic

= 0.3, (c) I

/Ic

= 0.5, (d) I

/Ic

= 0.7.

0 20 40 60 80 100

0 deg

30 deg

60 deg

(/m/Hz)

(mT)

= 0.3

(a)

f = 26.62 Hz

0 20 40 60 80 100

(mT)

= 0.5

(b)

(/m/Hz)

0 20 40 60 80 100

(mT)

= 0.7

(c)

(/m/Hz)

5E-4

1E-3

0 20 40 60 80 100

= 0.7

= 0.5

= 0.3

(/m/Hz)

a, //

(mT)

f = 26.62 Hz

0 20 40 60 80 100

0 deg

30 deg

60 deg

(/m/Hz)

(a)

= 0.3

f = 26.62 Hz

cos (mT)

0 20 40 60 80 100

(b)

(/m/Hz)

= 0.5

cos (mT)

0 20 40 60 80 100

(c)

(/m/Hz)

= 0.7

cos (mT)

Dynamic Resistance Measurements in a GdBCO-Coated Conductor

Figures

Citations

Numerical modelling of dynamic resistance in high-temperature superconducting coated-conductor wires

Numerical Modeling of Dynamic Loss in HTS-Coated Conductors Under Perpendicular Magnetic Fields

The dynamic resistance of YBCO coated conductor wire: Effect of DC current magnitude and applied field orientation

Dynamic loss and magnetization loss of HTS coated conductors, stacks, and coils for high-speed synchronous machines

Dependence of Dynamic Loss on Critical Current and n -Value of HTS Coated Conductors

References

Type-II-superconductor strip with current in a perpendicular magnetic field.

Applications of High Temperature Superconductors to Electric Power Equipment

Review of high power density superconducting generators: Present state and prospects for incorporating YBCO windings

Dynamic resistance of a high-Tc superconducting flux pump

Applications of High Temperature Superconductors to Electric Power Equipment: Kalsi/Applications of High Temperature Superconductors

Related Papers (5)

Dynamic resistance of a high-T c coated conductor wire in a perpendicular magnetic field at 77 K

Dynamic resistance in a slab-like superconductor with Jc(B) dependence

Generation of a dc voltage by an ac magnetic field in type-II superconductors

Dynamic resistance of a high-Tc superconducting flux pump

Type-II-superconductor strip with current in a perpendicular magnetic field.

Frequently Asked Questions (11)

Q1. What are the contributions mentioned in the paper "Dynamic resistance measurements in a gdbco- coated conductor" ?

Q2. What is the effect of the flow loss on the sample?

Q3. Why is the value of the threshold magnetic field given in Fig. 3?

Q4. What are the possible causes of the dc/ic0 discrepancy?

Q5. What is the amplitude of the applied magnetic field?

Q6. What is the maximum of the curve?

Q7. What was the purpose of the experiment?

Q8. How does the dynamic resistance of a GaBCO coated conductor be determined?

Q9. How many times did the authors measure Bth?

Q10. What is the effect of the high aspect ratio of the coated conductor wire?

Q11. How is the dynamic resistance per unit length per cycle in a superconducting strip?