PPT Slide

• Total energy is thus 4 x 10 J Assume 1 SN every 100 years for 10 years => total energy due to pulsars : 4 x 10 x 10 J = 4 x 10 J in a volume of ~10 m (ie. the Galaxy)

• => energy density of electrons produced by pulsars : =4 x 10 J m = 4 x 10 J m = 4 x 10 / 1.6 x 10 eV m = 2.5 x 10 eV m

40

10

40

8

48

63

48-63

-3

-3

-15

-15

-19

-3

4

-3

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So the total energy produced in electrons by the Crab pulsar is 4e40J. Assuming 1 supernova every 100 years for the lifetime of the Galaxy (10 billion years), we find that 4e48J has been produced in a volume of 1e63m^3.

This gives an energy density of electrons produced by pulsars of 2.5e4 eV/m^.

Remember that the observed electron energy density is 4e3 eV/m^3, so electron emissions from pulsars are sufficient to produce observed levels, given the assumptions made.