Combined Effects Of Mass Flow And Particle Diffusion On The Ionization Structure Of The Solar Transition Region

Details Combined Effects Of Mass Flow And Particle Diffusion On The Ionization Structure Of The Solar Transition Region Combined Effects Of Mass Flow And Particle Diffusion On The Ionization Structure Of The Solar Transition Region

Oct 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999esasp.446..141a&link_type=abstract

8th SOHO Workshop: Plasma Dynamics and Diagnostics in the Solar Transition Region and Corona. Proceedings of the Conference hel

Astronomy and Astrophysics

Astrophysics

4

Scientific paper

The transition region between the top of the chromosphere (T < 10,000 K) and the lowest part of the corona (T > 100,000 K) is known to have a thickness of only a few kilometers. This is the temperature range in which there is maximum radiative cooling in the strong resonance lines of H, HeI, and HeII. The heat input that balances this radiative cooling appears to come from the low corona rather than from local mechanical heating. Detailed models of the transition region without the effects of mass flow have been published by Fontenla, Avrett, and Loeser (1993). They solved the complete set of radiative transfer, statistical equilibrium, and energy balance equations for H, HeI, and HeII, balancing the cooling due to optically thick, non-LTE radiative transitions with the heating due to the transport of energy from higher temperatures by thermal conduction and particle diffusion. The resulting theoretical models showed better agreement with observations than earlier empirical models based on local statistical equilibrium without particle diffusion. Shown here are our first results of the more complicated calculations that include the additional effects of mass flows. We consider mass-conserving outflow and inflow velocities having values up to 8 km/s in the upper transition region. The hydrogen Lyman lines are not highly sensitive to such flows, but the resonance lines of HeI and HeII show pronounced effects as a result of ionization balance changes. Outflow causes greater amounts of HeI at higher temperatures and inflow causes greater amounts of HeIII at lower temperatures compared with zero-flow ionization equilibrium. As before, these calculations include particle diffusion, i.e., ions penetrate into nearby neutral regions and neutrals into nearby ionized regions. We find that particle diffusion remains important even for the highest flow velocities we have considered.

Affiliated with

Also associated with

No associations

Rating

Combined Effects Of Mass Flow And Particle Diffusion On The Ionization Structure Of The Solar Transition Region does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Combined Effects Of Mass Flow And Particle Diffusion On The Ionization Structure Of The Solar Transition Region, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Combined Effects Of Mass Flow And Particle Diffusion On The Ionization Structure Of The Solar Transition Region will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1084695