Interstellar Shock Waves Mark Wardle
Interstellar Shock Waves Mark Wardle
Interstellar Shock Waves Mark Wardle
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Astrophysical shock waves<br />
• Cosmic violence: shock waves are common<br />
sound speed: cs =<br />
� kT<br />
m<br />
�<br />
T /1000K<br />
≈ 3km/s ×<br />
m/mp<br />
� 1/2<br />
Alfvén speed: vA = B<br />
B/µG<br />
� ≈ 2 km/s ×<br />
4πρ (nH/cm−3 ) 1/2<br />
– stellar winds, cloud collisions, supernovae, accretion, jets, . . .<br />
• <strong>Shock</strong> waves process the gas<br />
– change density, velocity and temperature<br />
– affect ionization state, destroy dust grains, drive chemistry<br />
– introduce structure into the fluid<br />
– particle acceleration<br />
– shocked gas radiates!<br />
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