def sigma(self):
        """
        Spot size of matched beam :math:`\\left( \\frac{2 E \\varepsilon_0 }{ n_p e^2 } \\right)^{1/4} \\sqrt{\\epsilon}`
        """
        return _np.power(2*_sltr.GeV2joule(self.E)*_spc.epsilon_0 / (self.plasma.n_p * _np.power(_spc.elementary_charge, 2)) , 0.25) * _np.sqrt(self.emit)
def sigma(self):
        """
        Spot size of matched beam :math:`\\left( \\frac{2 E \\varepsilon_0 }{ n_p e^2 } \\right)^{1/4} \\sqrt{\\epsilon}`
        """
        return _np.power(2*_sltr.GeV2joule(self.E)*_spc.epsilon_0 / (self.plasma.n_p * _np.power(_spc.elementary_charge, 2)) , 0.25) * _np.sqrt(self.emit)
def sigma ( self ) : return _np . power ( 2 * _sltr . GeV2joule ( self . E ) * _spc . epsilon_0 / ( self . plasma . n_p * _np . power ( _spc . elementary_charge , 2 ) ) , 0.25 ) * _np . sqrt ( self . emit )
Spot size of matched beam :math:`\\left( \\frac{2 E \\varepsilon_0 }{ n_p e^2 } \\right)^{1/4} \\sqrt{\\epsilon}`
Spot size of matched beam : math : \\ left ( \\ frac { 2 E \\ varepsilon_0 } { n_p e^2 } \\ right ) ^ { 1 / 4 } \\ sqrt { \\ epsilon }