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Hankel Function of the First Kind


The Hankel functions of the first kind are defined as

 H_n^((1))(z)=J_n(z)+iY_n(z),
(1)

where J_n(z) is a Bessel function of the first kind and Y_n(z) is a Bessel function of the second kind. Hankel functions of the first kind is implemented in the Wolfram Language as HankelH1[n, z].

Hankel functions of the first kind can be represented as a contour integral over the upper half-plane using

 H_n^((1))(z)=1/(ipi)int_(0 [upper half plane])^infty(e^((z/2)(t-1/t)))/(t^(n+1))dt.
(2)

The derivative of H_n^((1))(z) is given by

 d/(dz)H_n^((1))(z)=(nH_n^((1))(z))/z-H_(n+1)^((1))(z).
(3)
HankelH1ReIm
HankelH1Contours

The plots above show the structure of H_0^((1))(z) in the complex plane.


See also

Bessel Function of the First Kind, Bessel Function of the Second Kind, Debye's Asymptotic Representation, Hankel Function of the Second Kind, Spherical Hankel Function of the First Kind, Watson-Nicholson Formula, Weyrich's Formula

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References

Arfken, G. "Hankel Functions." §11.4 in Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 604-610, 1985.Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 623-624, 1953.

Referenced on Wolfram|Alpha

Hankel Function of the First Kind

Cite this as:

Weisstein, Eric W. "Hankel Function of the First Kind." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/HankelFunctionoftheFirstKind.html

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