49{
52 G4double x = a*yTrack[0], y = a*yTrack[1], z = a*yTrack[2] ;
53 G4double x2 = x*x, y2 = y*y, z2 = z*z, r2 = x2 + y2 ;
54 G4double r4 = r2*r2, z4 = z2*z2, r6 = r4*r2, z6 = z4*z2 ;
55 G4double r8 = r4*r4, z8 = z4*z4, r10 = r8*r2, z10 = z8*z2 ;
56 G4double rz = z*std::sqrt(r2), r = std::sqrt(r2+a*a) ;
60 -9.26e-5, -3.51e-5, 2.94e-6, -1.10e-6,
61 6.25e-8, -1.77e-8, -6.88e-10, -7.52e-11
62 } ;
63 P[0] = 2*rz ;
64 P[1] = 4*rz*(r2 - 4.0*z2/3.0) ;
65 P[2] = 6*rz*(r4 - 4*r2*z2 + 1.6*z4) ;
66 P[3] = 8*rz*(r6 - 8*r4*z2 + 9.6*r2*z4 - 64.0*z6/35.0) ;
67 P[4] = 10*rz*(r8 - 40.0*r6*z2/3.0 + 32*r4*z4
68 - 128.0*r2*z6/7.0 + 128.0*z8/63.0);
69 P[5] = 0 ;
70 P[6] = 0 ;
71 P[7] = 0 ;
72
73 Q[0] = r2 - 2*z2 ;
74 Q[1] = r4 - 8*r2*z2 + 8.0*z4/3.0 ;
75 Q[2] = r6 - 18*r4*z2 + 24*r2*z4 - 3.2*z6 ;
76 Q[3] = r8 - 32*r6*z2 + 96*r4*z4 - 51.2*r2*z6 +128.0*z8/35.0 ;
77 Q[4] = r10 - 50*r8*z2 + 800.0*r6*z4/3.0 - 320*r4*z6
78 + 640.0*r2*z8/7.0 - 256.0*z10/63.0 ;
79 Q[5] = 0 ;
80 Q[6] = 0 ;
81 Q[7] = 0 ;
82
83 Br = 0 ;
84 B[2] = 1.2*tesla ;
86 {
87 Br += c[i]*P[i] ;
88 B[2] += c[i]*Q[i] ;
89 }
90 B[0] = Br*x/r ;
91 B[1] = Br*y/r ;
92 return ;
93}