An estimate of electron densities in the exosphere by means of nose whistlers

Abstract

The nose whistler dispersion equation was numerically integrated using the following assumed functions for the electron density distribution: (1)N=K (2) N = KR−3. (3) N = KR−3 exp(3.03/R). N is the electron number density, R is the distance from the earth's center, and K a constant of proportionality. Several whistlers that were received at College on March 19, 1959, were analyzed to obtain electron densities. Each of these whistlers consists of a number of branches having successively lower nose frequencies. Measurements of the nose frequencies and the time of propagation of the nose frequency yield values of the constant K from which the electron density can be determined at any point. It was found that the results for the first two functions disagree systematically with the curve of the assumed function. The third function, suggested by F. S. Johnson on the basis of theoretical considerations, fits the data well within the experimental errors. The resulting distributions cover the range between 4 and 6 earth's radii, giving densities varying from 20 to 5 electrons per cubic centimeter.

Geomagnetically trapped electrons from cosmic ray albedo neutrons

“…The neutral hydrogen distribution in the exosphere has been determined by Opik and Singer [1961], the relative distribution being calculated from theory, the normalization being The model which we adopt for the purpose of calculating trapped particle intensities is obtained from these sources and is shown in Table 1. The effective densities as defined in Appendix I are shown in Figure 4 and compared with results of Allcock [1959] and Pope [1961], together with a theoretical distribution calculated by Johnson [1960]. It should be pointed out explicitly that we are neglecting the rather large time variations which certainly exist for all of the components.…”

Global core plasma model

“…">IntroductionBy mass, the magnetosphere is dominated by plasma with energies below 100 eV. Beginning with the earliest ground-based whistler [Storey, 1953;Pope, 1961;Smith, 1961 ] and spacecraft [Gringauz et al, 1960a, b] observations, these core plasmas have been studied for many years. Plasma wave frequencies, particle heating, and instability growth rates can be strongly influenced by the presence and concentrations of core plasmas.…”

World-wide changes in the geomagnetic field

“…Chapman and Ferraro [1931] demonstrated that these changes can be produced when a highly ionized corpuseular stream is propagated from the sun across the empty space between the sun and earth, and pushes inward on the geomagnetic field. Modifications of their theory were presented later, since it was found that a highly conductive eorpuseular stream is flowing out continuously from the sun [Bierman, 1957] and that the space inside the geomagnetic field is filled with sufficient plasma to be a good electrical conductor [Storey, 1953;and Pope, 1961]. It is now considered that, the geomagnetic field is always confined to a region of finite dimensions under the influence of a continuously flowing eorpuscular stream [Dungey, 1954;Hoyle, 1956;Parker, 1958;Obayashi, 1958;and Beard, 1960].…”