The Solar Wind

. ~ydrodyn~mic expansion of the solar corona is the basis for "solar corpusc ular radiatIOn . The qUiet day coronal temperatures of 1 to 2X 106 OK yield a solar wind of several h';lDdred km/sec and a density of 5 to 50 particles/cm3 at the orbit of Earth. The solar ~lVllld draws out m to spa~e t he. lines of fore.e of t he gen eral one-gauss solar field, to give an Il1terplanetary fi eld t hat IS baSICally spiral III character with a densitv of the order of a few tim~s 105 gaus~ ~t }he. orbi~ o! Eart~ . The enhanced corona may sometimes h3;ve temperatlll es of 4 X 10 h Ot mOl e Il1une(liately folloWIl1g a large fl a re. Such explOSIve heating leads to a 1 to 2X 103 ~m/sec blast wave into planetary sp ace. The blast wave sweeps up t he qLllet-day. solar wmd a head and kinks the quiet-day fi eld, r aising the density of t he field to several tImes 104 ga us.3 o.n some occasions. The ga.lactic cosmic ray particles are slVept back by ~he lunk, j)l'oducll1g a .Forbush-type Il1tenSlty decrease. Altogether , the blast w!lve and Its magnetic fi eld constitute t he "en hanced solar corpuscular radiation." It IS shown that ~!le alte t; :1a~lve magnetic tongue model of Gold and others [1960] is untenab le because the to ngue \I ould not r each t he ear th untIl many hours after t he arrival of the blast wave.