
TY  - JOUR
A1  - Gould, RJ 
T1  - Emission and Absorption of Radio Waves in the Galactic Disk
JF  - Australian Journal of Physics
JO  - Aust. J.  Phys.
Y1  - 1969
VL  - 22
IS  - 2
SP  - 189
EP  - 200
KW  - 
UR  - https://doi.org/10.1071/PH690189 
N2  - Bremsstrahlung in electron collisions with helium atoms produces up to O' 04 % of the radio emission continuum from the main part of interstellar HII regions, while, near the outer edge where hydrogen is about half-ionized, electron collisions with hydrogen atoms produce up to 2% of the normal electron-proton bremsstrahlung. Radio emission and absorption in electron-hydrogen and electron-helium collisions in HI regions are investigated and found to be negligible at the low temperatures therein. However, low energy cosmic rays may ionize HI regions to a sufficient degree to significantly attenuate radio waves by inverse bremsstrahlung (free-free absorption) in electron-proton Coulomb collisions. Future high resolution surveys of the cosmic radio brightness should be able to distinguish between HI and Ell absorption. 
ER  -

