Patent ID: 7060985

Claim:
An apparatus for producing a 2n-pole field (n=1, 2, 3, . . . ) using at least one magnetic or electrostatic 2n-pole element, wherein strength I k (1≦k≦2n) of the kth pole in the 2n-pole element is controlled with control parameters A, C j , and θ j (1≦j≦n−1), based on a control formula given by I k = A ⁡ ( cos ⁡ ( k ⁢ ⁢ π ) + C 1 ⁢ cos ⁡ ( θ 1 + k ⁢ ⁢ π / n ) + C 2 ⁢ cos ⁢ ⁢ 2 ⁢ ( θ 2 + k ⁢ ⁢ π / n ) + C 3 ⁢ cos ⁢ ⁢ 3 ⁢ ( θ 3 + k ⁢ ⁢ π / n ) + ⋯ + C n - 1 ⁢ cos ⁡ ( n - 1 ) ⁢ ( θ n - 1 + k ⁢ ⁢ π / n ) ) and wherein the parameter A is varied continuously at frequency f with respect to real time t given by A=B cos(2π tf ).