code: def j0_4(f=1, rho=0.3, z=50):
      r
  
      gam = np.sqrt(2j*np.pi*mu_0*f/rho)
  
      def lhs(x):
          beta = np.sqrt(x**2 + gam**2)
          return x*np.exp(-beta*np.abs(z))/beta
  
      def rhs(b):
          R = np.sqrt(b**2 + z**2)
          return np.exp(-gam*R)/R
  
      return Ghosh('j0', lhs, rhs)
docs: r"""Hankel transform pair J0_4 ([ChCo82]_).
  
      Parameters
      ----------
      f : float
          Frequency (Hz)
      rho : float
          Resistivity (Ohm.m)
      z : float
          Vertical distance between source and receiver (m)