Fr.: rayon de balayage
The → radius of a → supernova remnant (SNR) when, at the end of the → free expansion phase, the mass of the swept-up → shell equals that of the ejected gas from the → supernova explosion. It is given by RSW = (3Me / 4πρ0)(1/3), where Me is the ejected mass and ρ0 is the initial density of the → interstellar medium.
Sweep, from M.E. swepen, from O.E. swapan "to sweep;" cognate with Ger. schweifen; → up; → radius.
Šo'â', → radius; rubeš, noun from ruftan, rubidan "to sweep," → scan.