712 



TABLE 797.— THE CRITICAL ENERGY* AND THE TOTAL ENERGY OF 

 COSMIC RAYS ENTERING THE ATMOSPHERE AT FOUR LOCATIONS 



Location 

 Saskatoon . 

 Omaha .... 



60° 

 51° 



1.4 

 2.9 



bjc, 



GO U 



2 a v 



2.36 

 2.25 



Location 



San Antonio 

 Madras . . . . 



E.5 

 38° 



6.7 

 17.0 



>;§ 



tso° 

 n) oj r, 



1.81 

 .94 



The energy of a cosmic ray which enables it to enter the earth's atmosphere. 



TABLE 798.— ESTIMATED COSMIC RAY INTENSITIES AT 50° GEOMAGNETIC 



LATITUDE 



In this table are given some data on cosmic rays for various altitudes for geomagnetic lati- 

 tudes of 50° 



TABLE 799.— SOME COSMIC-RAY DATA 



Total number of rays at top of the atmosphere 8X10 17 sec -1 



Total energy carried to earth per second (outer atmos- 

 phere) 9X10 18 Bev/sec, 1.4X10 9 watts 



If all particles are positively charged this stream gives 

 a current of * 13 amp 



Average number of rays t at top of atmosphere 16 cm" 2 sec" 1 



Average energy of all incident particles, latitude >40. ... 7 Bev 



Average energy of all incident particles, all areas, about. . 11 Bev 



Cosmic energy reaching earth's outer atmosphere, high 



latitude 3.8X10" 3 erg cm" 2 sec" 1 



Average energy of the cosmic rays entering the atmos- 

 phere is about 7X 10" ev 



The spectrum extends from about 1X10" to 10 17 ev and probably higher 



The energy required for the ionization found in a column 

 1 cm 2 in cross section extending to top of atmosphere 

 at 60 N geomagnetic latitude 3.8X 10" s erg cm" 2 sec" 1 



Thus in this column there are formed about 7.4X10 7 ion pairs 



This means about 90 ion pair, cm" 1 sec" 1 



Total number of rays at sea level from all directions 1.2 ray min" 1 cm" 2 



Cosmic ray at sea level produces t 1.63 ion pair, cm" 1 sec" 1 



Total cosmic energy reaching earth per second at sea level. 40 joules 



Radiant energy flux reaching earth from all stars 3.02X10" 8 erg cm" 2 sec" 1 



If there were no compensating effects the potential of the earth would increase about lSOF/sec. t The 



number varies with the geomagnetic latitude, being about 0.33 particles cm- 2 sec" 1 at high latitudes (>40°) 

 and about 0.032 particles cm -2 sec" 1 at the equator. This data is based upon an energy of 32 ev necessary to 

 produce one ion pair. t Thus the average ray entering the cm 3 at sea level has an energy of about 10 a ev. 



SMITHSONIAN PHYSICAL TABLES 



