# wavenumber¶

empymod.kernel.wavenumber(zsrc, zrec, lsrc, lrec, depth, etaH, etaV, zetaH, zetaV, lambd, ab, xdirect, msrc, mrec)[source]

Calculate wavenumber domain solution.

Return the wavenumber domain solutions PJ0, PJ1, and PJ0b, which have to be transformed with a Hankel transform to the frequency domain. PJ0/PJ0b and PJ1 have to be transformed with Bessel functions of order 0 ($$J_0$$) and 1 ($$J_1$$), respectively.

This function corresponds loosely to equations 105–107, 111–116, 119–121, and 123–128 in [HuTS15], and equally loosely to the file kxwmod.c.

[HuTS15] uses Bessel functions of orders 0, 1, and 2 ($$J_0, J_1, J_2$$). The implementations of the Fast Hankel Transform and the Quadrature-with-Extrapolation in empymod.transform are set-up with Bessel functions of order 0 and 1 only. This is achieved by applying the recurrence formula

(1)$J_2(kr) = \frac{2}{kr} J_1(kr) - J_0(kr) \ .$

Note

PJ0 and PJ0b could theoretically be added here into one, and then be transformed in one go. However, PJ0b has to be multiplied by ang_fact later. This has to be done after the Hankel transform for methods which make use of spline interpolation, in order to work for offsets that are not in line with each other.

This function is called from one of the Hankel functions in empymod.transform. Consult the modelling routines in empymod.model for a description of the input and output parameters.

If you are solely interested in the wavenumber-domain solution you can call this function directly. However, you have to make sure all input arguments are correct, as no checks are carried out here.