1995A&A...293..565F

The paper examines the lowest frequency observations of the galactic radio noise published by Brown (1973ApJ...180..359B) and their relationship to the properties of the local interstellar medium. We find that the Razin cut-off frequency in the warm gas is about 0.3MHz and nearly constant, which provides a sharp decrease of the galactic spectrum at f<0.6MHz. The synchrotron emissivity in the tenuous (coronal) gas is found to be much less than that in the warm gas, while it is responsible for the observed excess of the emission at 0.13<f<0.25MHz. Transition radiation of relativistic electrons on small scale plasma fluctuations may contribute about 10-20% to the observed emission at f=0.13MHz and determine the total spectrum at lower frequencies if we accept the fluctuation level found from pulsar scintillations and some realistic distribution of the mean plasma density. Compton emission on small scale magnetic and electric fields is shown to be unimportant in the specified conditions. We conclude that new observations at lower frequencies are required to obtain further important knowledge on free electron inhomogeneous distribution in the very local interstellar medium.