Theory of the Fireball
Theory of the Fireball
Theory of the Fireball
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with C = 14.<br />
and find<br />
On this basis we calculate <strong>the</strong> outer radius R <strong>of</strong> <strong>the</strong> warm layer<br />
2<br />
Using (6.17) we can <strong>the</strong>n calculate €$/Rae We give t'nis quantity in <strong>the</strong><br />
second last line <strong>of</strong> Table IX. In Yne last line, we nave given <strong>the</strong> mate-<br />
rial thickness <strong>of</strong> <strong>the</strong> warm layer, in relative units,<br />
L' = p2 - R2 - R1<br />
'a Ra<br />
It is seen from <strong>the</strong> table that R increases only sluwly; <strong>the</strong> main<br />
2<br />
change in R - R1 at later times is <strong>the</strong>refore due to <strong>the</strong> decrease <strong>of</strong> R<br />
2 I'<br />
The material thickness L' first decreases very slightly; this continues<br />
about as long as R increases, and is due to <strong>the</strong> fact that about <strong>the</strong> same<br />
1<br />
mass <strong>of</strong> warm material gets distributed over a larger area. Later on, L'<br />
increases while R decreases. Until x = 2.5 <strong>the</strong> chaage <strong>of</strong> L' remains<br />
1<br />
less than lo%, and after x = 2.5 <strong>the</strong> calculation is probably meaningless<br />
because <strong>the</strong> bomb debris comes into view. Therefore, we 'may assume L'<br />
constant, and thus <strong>the</strong> optical mass slbsorption coefficient (in cm 2 /gm)<br />
at <strong>the</strong> radiating layer will also be constant. In contrast with this<br />
79<br />
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