Bispherical Coordinates


BisphericalCoordinates

BisphericalCoordinates3D

A system of curvilinear coordinates variously denoted (xi,eta,phi) (Arfken 1970) or (theta,eta,psi) (Moon and Spencer 1988). Using the notation of Arfken, the bispherical coordinates are defined by

Surfaces of constant eta are given by the spheres

x^2+y^2+(z-acotheta)^2=(a^2)/(sinh^2eta),

(4)

surfaces of constant xi by apple surfaces (xi<pi/2) or lemon surfaces (xi>pi/2)

x^2+y^2+z^2-2asqrt(x^2+y^2)cotxi=a^2,

(5)

and surface of constant psi by the half-planes

tanphi=y/x.

(6)

The scale factors are

The Laplacian is given by

del ^2f=((cosheta-cosxi)^3)/(a^2sinxi){sinxipartial/(partialeta)(1/(cosheta-cosxi)(partialf)/(partialeta))+partial/(partialxi)((sinxi)/(cosheta-cosxi)(partialf)/(partialxi))}+((cosheta-cosxi)^2)/(a^2sin^2xi)(partial^2f)/(partialphi^2).

(10)

In bispherical coordinates, Laplace's equation is separable (Moon and Spencer 1988), but the Helmholtz differential equation is not.


See also

Bicyclide Coordinates, Laplace's Equation--Bispherical Coordinates, Spherical Coordinates, Toroidal Coordinates

Explore with Wolfram|Alpha

References

Arfken, G. "Bispherical Coordinates (xi,eta,phi)." ยง2.14 in Mathematical Methods for Physicists, 2nd ed. Orlando, FL: Academic Press, pp. 115-117, 1970.Moon, P. and Spencer, D. E. "Bispherical Coordinates (eta,theta,psi)." Fig. 4.03 in Field Theory Handbook, Including Coordinate Systems, Differential Equations, and Their Solutions, 2nd ed. New York: Springer-Verlag, pp. 110-112, 1988.Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 665-666, 1953.

Referenced on Wolfram|Alpha

Bispherical Coordinates

Cite this as:

Weisstein, Eric W. "Bispherical Coordinates." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/BisphericalCoordinates.html

Subject classifications