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Flux Jumps in Magnetization of HTS Tubes. Nasser S. Alzayed Physics Dept., King Saud University Riyadh 11451, Saudi Arabia

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Presentation on theme: "Flux Jumps in Magnetization of HTS Tubes. Nasser S. Alzayed Physics Dept., King Saud University Riyadh 11451, Saudi Arabia"— Presentation transcript:

1 Flux Jumps in Magnetization of HTS Tubes. Nasser S. Alzayed Physics Dept., King Saud University Riyadh 11451, Saudi Arabia

2 Magnetic Shields Superconductors are Expected to Shield the applied Magnetic Fields This Phenomenon is called Missner Effect. The phenomenon take place because the Superconductor creates a screening current that creates an opposite and equal mag. Field

3 Vortices When The applied mag. Field is large enough, > H C1, magnetic Fluxions (vortices) will spread all over the material However Material is still superconducting (Type II Only)

4 Large Fields When H ext is larger than H C2, superconductivity will be destroyed altogether.

5 So …!!! As long as the H ext is < H C1, no Flux penetration should occur. No Flux Creep is expected. Flux Avalanche is not possible.

6 Flux Creep Model H/H C Thickness

7 Bean Model Bean Model has been Used since the 60’s to explain for the phenomenon. This model assumes the fulfillment of the local adiabatic conditions for the sample.

8 Bean Model Simulation Thickness J/J C

9 Blue Region is Superconducting Strip Magnetic Field is Perpendicular to Strip All Values are normalized Pining Energy used is: H(X) Top M(H) Bottom J(x) middle

10 When Jumps Happen? We noticed that Jumps took place at very small values. Much Less than H C In this case adiabatic conditions have nothing to do with Flux avalanche

11 Creep Is impossible Our Flux is detected inside the Tube. Hence it is not due to Flux Creep.

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17 Conclusion These Flux Jumps happen at small values Hence They cannot be attributed to Flux Creep They cannot be due to Flux avalanche We think this is a quantum phenomenon

18 ENDEND


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