def METHOD_NAME(field, data):
    MJ_constant = (((5.0 * pc.kboltz) / (pc.G * pc.mh)) ** 1.5) * (
        3.0 / (4.0 * np.pi)
    ) ** 0.5
    u = (
        MJ_constant
        * (
            (data[ftype, "temperature"] / data[ftype, "mean_molecular_weight"])
            ** 1.5
        )
        * (data[ftype, "density"] ** (-0.5))
    )
    return u