Engineering topics

Diodato, L.

Publications and source records attributed to Diodato, L..

2 records

NASA NTRS1976

A statistical study of the upstream wave boundary outside the earth's bow shock

The location of the forward boundary of the upstream wave region ahead of the earth's bow shock is investigated statistically using plasma and magnetic-field data obtained by Heos 1. The analysis is conducted on the assumption that the waves are produced by protons reflected from the bow shock and traveling upstream with an effective velocity equal to the product of a parameter, p, and the solar-wind bulk velocity. The data-reduction methods are summarized, and uncertainties in the determination of the value of p are discussed. It is found that the overall average boundary corresponds to a velocity of approximately twice the solar-wind velocity for protons reflected from the daytime sector of the bow shock. More refined analysis of the data shows that the value of p is approximately 1.6 near the subsolar point and greater than 2 along the daytime flanks of the bow shock.

Diodato, L.↗

NASA NTRS1974

Long-term variations of the solar wind proton parameters

Interplanetary plasma data taken near 1 AU by a variety of spacecraft (Imp 1, Vela 2-4, Explorer 33-35, and Heos 1) from 1963 to 1971 are used to study the long-term variations of the solar wind proton properties. An intercalibration among the different experiments is performed in order to obtain a coherent set of data. The most interesting result is a 40% reduction of the proton density between the minimum and the maximum of the solar activity cycle. The observed density variation occurs throughout the velocity range; however, a limited sample of data could suggest that at very low velocities (below 300 km/sec) the density is independent of the solar activity. The proton bulk velocity is remarkably constant during the period considered; small increases of the average speed occurring in 1968 and 1971 cannot be attributed to the solar cycle. No clear trend is exhibited by the proton temperature; differences among the various experiments probably have an instrumental origin.

Diodato, L.↗