Dynamics of Step Heat Waves in Gases and Plasmas

Ahlborn, B.; Strachan, J.

doi:10.1139/p73-188

Cited by 21 publications

(2 citation statements)

References 3 publications

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“…This creates a rearward-facing, i.e. in the opposite direction to the IF, rarefaction wave and a forward-facing shock (Strachan and Ahlborn 1975;Ahlborn and Strachan 1973). Under homogeneous conditions and for an infinite flow stream these waves and shocks will form periodically (Schnerr & Adam 1997).…”

Section: Supersonic Ionization Fronts and Cooling Frontsmentioning

confidence: 99%

IONIZATION-DRIVEN FRAGMENTATION OF GAS OUTFLOWS RESPONSIBLE FOR FeLoBALs IN QUASARS

Bautista¹,

Dunn²

2010

ApJ

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We show that time variations in the UV ionizing continuum of quasars, on scales of ∼1 year, affect the dynamic structure of the plasmas responsible for low ionization broad absorption lines. Variations of the ionizing continuum produce non-equilibrium photoionization conditions over a significant fraction of the absorbing clouds and supersonically moving ionization fronts. When the flux drops the contraction of the ionized region drives a supersonic cooling front towards the radiation source and a rarefaction wave in the opposite direction. The pressure imbalance is compensated by an increased speed of the cool gas relative to the front. When the flux recovers the cool gas is re-ionized and re-heated by a supersonic ionization front traveling away from the radiation source and a forward shock is created. The reheated clouds equilibrate to a temperature of ∼ 10 4 K and are observed to have different radial velocities than the main cloud. Such fragmentation seems consistent with the multicomponent structure of troughs seen in some objects. The velocity differences measured among various components in the quasars QSO 2359-1241 and SDSS J0318-0600 can be reproduced by our model if strong magnetic fields (∼10 mG) are present within the clouds.

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Section: Supersonic Ionization Fronts and Cooling Frontsmentioning

confidence: 99%

IONIZATION-DRIVEN FRAGMENTATION OF GAS OUTFLOWS RESPONSIBLE FOR FeLoBALs IN QUASARS

Bautista¹,

Dunn²

2010

ApJ

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“…The properties of heat waves have been described in detail by Ahlborn and Strachan (1973), and we review here only those properties relevant to the effect under consideration. The term heat wave is used to describe a zone of strong change in enthalpy h, which is produced whenever an energy flux of intensity W (Wm-2 ) is locally deposited into a gas of density p. This heat wave travels with some characteristic velocity V ex W / ph through the medium and generates a pressure wave, or zone of strong momentum change, travelling with a velocity U.…”

Section: Heat Wavesmentioning

confidence: 99%