The solar flux unit (sfu) is a convenient measure of spectral flux density often used in solar radio observations, such as the F10.7 solar activity index:^[1]

1 sfu = 10⁴ Jy = 10⁻²² W⋅m⁻²⋅Hz⁻¹ = 10⁻¹⁹ erg⋅s⁻¹⋅cm⁻²⋅Hz⁻¹.

See jansky for further information about related units.