On Excessive Resistance and Heat Generation of Aluminum Conductor Due to Magnetic Field Inhomogeneity
One of major problem of cryogenic devices generating high magnetic field is an enhancement of magnetoresistance and respective heat generation due to inhomogeneity of composite conductor in the place of its interface. It should be mentioned that there is an inhomogeneity of magnetic field through device’s coils because the inner and outer coils are at different magnitudes of magnetic field. Usually a contribution of magnetic field inhomogeneity into resistance increase is neglected. A paper proposed here is to show that at cryogenic temperatures the amount of excessive resistance connected with magnetic field inhomogeneity may be comparable in magnitude with traditional enhancement of resistance due to interface of composite conductors. The testing is done by measurement of potential distribution over aluminum conductors being under inhomogeneous magnetic field action at 4.2 K. The magnetic field gradient up to 35 kOe/cm is directed along current flow. A calculation of nonuniform current distribution and enhancement of resistance due to decrease of effective conductor cross section is made. A correlation of experimental data with calculation is established and discussed.
KeywordsMagnetic Field Magnetic Field Gradient Resistance Ratio Inhomogeneous Magnetic Field Composite Conductor
Unable to display preview. Download preview PDF.
- 4.O.R.Christianson and J.H.Parker, Anomalous magnetoresistance mechanisms, in: “Advances in Cryogenic Engineering (Materials)”, Plenum Press, New York and London (1994), v.40A, p. 4. 25.Google Scholar
- 5.N.Yanagi, T.Mito, K.Takahata, M.Sakamoto, et all, Experimental observation of anomalous magnetoresistivity in 10–20 kA class aluminum-stabilized superconductors for the large helical device, in:“Advances in Cryogenic Engineering (Materials)”, Plenum Press, New York and London (1994), v. 40A, p. 459.Google Scholar
- 7.V.I.Gostishchev, A.A.Drozd and S.E.Dem’yanov, Electric field distribution in aluminum in strong magnetic fields, Sov.J.Low Temp.Phys. 4: 532 (1978).Google Scholar
- 9.V.R.Sobol, O.N.Mazurenko and A.A.Drozd, Magnetostimulated inhomogeneity of electric field in aluminum, in: “Advances in Cryogenic Engineering (Materials)”, Plenum Press, New York and London (1996), v. 42, p. 1071.Google Scholar