High Solar Activity Years Research Articles

Primary Cosmic Ray and Solar Protons. II

During July and August, 1961, the energy spectrum of primary cosmic-ray protons was investigated in the energy range from 80 to 350 MeV. The observations were made in five high-altitude balloon flights at geomagnetic latitudes $\ensuremath{\lambda}\ensuremath{\ge}73$\ifmmode^\circ\else\textdegree\fi{} N. Solar flare and quiet day spectra were obtained. A comparison of the 1960 and 1961 results leads to the following conclusions: (1) A significant flux of low-energy protons is continually present in the primary radiation in the years of high solar activity. (2) This flux decreases with the declining level of solar activity as the galactic cosmic-ray flux increases. It is, therfeore, suggested that it is of solar origin. (3) The time dependence of the observed proton flux suggests the following alternatives: (a) The particles are produced or released more or less continuously by the sun and do not originate only in the large flare events; or (b) The particles are produced in individual large solar flares and subsequently stored over long periods of time. This second alternative would require a new and as yet unknown storage mechanism with a characteristic time of about 30 or more days.

On the occurrence of the [formula omitted] at Tokyo

From a statistical analysis on a basis of routine ionospheric observations at Tokyo (Kokubunji) throughout the last solar cycle, it is found that annual, seasonal and diurnal variations exist in the frequency of occurrence of the intermediate layer, the F1 1 2 - layer at the middle latitude of Tokyo. The F1 1 2 - layer appears mostly in the daytime and is prevalent at both equinoxes, especially remarkable in late spring during years of high solar activity—there has been good correlation between the frequency of occurrence and the number of sunspots.

Geomagnetic influence on the F1- and F2-regions of the ionosphere—effect of solar activity

The paper discusses the geomagnetic influence on the noon critical frequencies of F1- and F2-layers in different seasons and at different stages of solar activity. The F1-layer is found to be affected by the magnetic field only in years of high solar activity. The equatorial depression of noon ƒ 0F2 is, on the other hand, most prominent in years of low solar activity.

Experiments on the deflection of molecular beams in a magnetic field

Spread-F at equatorial stations, Ibadan, Djibouti and Kodaikanal is shown to increase with increasing solar activity. At Huancayo and other stations in the American zone there is least occurrence of spread-F in years of high solar activity. The seasonal variation of spread-F is greatest at stations in the American zone with a maximum in December and a minimum in June. At African stations a smaller seasonal variation is seen with maximum in June and minimum in December. At Asian stations the seasonal variation of spread-F is very small.