Title :
Simulation of Gradient-Coil-Induced Eddy Currents and Their Effects on a Head-Only HTS MRI Magnet
Author :
Poole, Michael ; Lopez, Hector Sanchez ; Ozaki, Osamu ; Kitaguchi, Hitoshi ; Nakajima, Iwao ; Urayama, Shin-ichi ; Sato, Ken-Ichi ; Fukuyama, Hidenao ; Crozier, Stuart
Author_Institution :
Sch. of Inf. Technol. & Electr. Eng., Univ. of Queensland, Brisbane, QLD, Australia
Abstract :
In this paper, we simulate the effects of eddy currents induced by switched gradient coils in the cylindrical cryostat structures of a high-temperature superconducting (HTS) magnetic resonance imaging magnet. A novel network method was used with spectral decomposition of the current density in the φ- and z-directions to simulate the effects of X-gradient coils. Two types of active magnetic shielding were simulated, and it was found that one type is able to reduce the power of the eddy currents in the cryostat to a greater extent than the other. These results will inform the design of gradient coils that protect the HTS magnet from eddy-current-induced heating and vibrations.
Keywords :
biomedical MRI; biomedical equipment; cryostats; eddy currents; high-temperature superconductors; superconducting magnets; HTS magnetic resonance imaging magnet; X-gradient coils; active magnetic shielding; current density; cylindrical cryostat structures; eddy-current-induced heating; eddy-current-induced vibrations; gradient-coil-induced eddy currents; head-only HTS MRI magnet; high-temperature superconducting MRI magnet; spectral decomposition; switched gradient coils; Eddy currents; High temperature superconductors; Magnetic noise; Magnetic resonance imaging; Magnetic shielding; Superconducting magnets; Eddy current; gradient coils; high-temperature superconducting (HTS); magnetic resonance imaging (MRI); network method;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2011.2166071
