A Review of the Saturation Induced Harmonics in the 80 mm Aperture RHIC Arc Dipole Magnets
- Brookhaven National Lab. (BNL), Upton, NY (United States)
In this note we shall review, at times with a sense of history, the measured and computed saturation induced harmonics in the cross section of all long and short 80 mm aperture RHIC dipole magnets built so far. A somewhat similar study for a fewer magnets has been presented earlier in reference 1. With the help of several iterations in the yoke cross section, we have been able to reduce the saturation induced b2 and b4 harmonics by more then an order of magnitude. We shall briefly describe those iterations. The calculations described in this note have generally been done with the program program POISSON. However, while comparing the calculations and measurements, we have included the results of field calculations with the code PE2D and MDP as well. The measurements are the average of up and down ramps. A small difference between the calculations and measurements has been observed consistently in the saturation induced b2 and b4 harmonics in all magnets DRA001 through DRA009. More work is still needed to explain the current dependence of skew quadrupole harmonic (α1). We refer to current dependence of harmonics loosely as the saturation induced harmonics; but in an actual magnet it inclludes other effects like the harmonics induced by the coil deformation due to lorentz forces, etc.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1119367
- Report Number(s):
- BNL-102025-2013-IR
- Country of Publication:
- United States
- Language:
- English
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