Synchrotron function

In mathematics the synchrotron functions are defined as follows (for x ≥ 0):

• First synchrotron function

$f(x)=x\int _{x}^{\infty }K_{\frac {5}{3}}(t)\,dt$

• Second synchrotron function

$f(x)=xK_{\frac {2}{3}}(x)$

where K_j is the modified Bessel function of the second kind.