1 / 12

Small Ionized and Neutral Structures…Theoretical Review

Small Ionized and Neutral Structures…Theoretical Review. “Minime me apud alios harum rerum perito, tamen dissereo…” Dante (circa 1320). TSAS: high density neutral atomic gas Received most attention in meeting Too bad there was not more attention given to connection.

alice
Download Presentation

Small Ionized and Neutral Structures…Theoretical Review

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Small Ionized and Neutral Structures…Theoretical Review “Minime me apud alios harum rerum perito, tamen dissereo…” Dante (circa 1320)

  2. TSAS: high density neutral atomic gas Received most attention in meeting Too bad there was not more attention given to connection ESE- “Extreme scattering events” Enhancements in plasma density, causing radio refraction B. Rickett, M. Walker Two Types of Small Scale Structure

  3. Statistical Fluctuations in Optical Depth (Deshpande) • If Desh is right, we just wasted three days of our lives! • Two obligations • (1) Every one other than Desh is obliged to read his paper • (2) Desh is obliged to right a second paper with equations in it

  4. Primary Problem with TSAS/ESE “Overpressure” in gas pressure by 10-1000 relative to canonical ISM value Comparison: Hurricane Katrina, dp/p ~ 10%

  5. Don Cox is right (not even controversial) • The magnetic field has to be included in pressure calculations. Pressure-balanced structures are standard plasma physics entities and are observed in solar wind. For B= 3 microGauss, nT = 2000

  6. Primary Result #1 • Ed Jenkins spectroscopic evidence for high pressure regions along line of sight. • Independent support for high nT zones

  7. Primary Result #2 (I’ll forget counting after this one) • Crystal Brogan result that Zeeman limits rule against magnetic compression

  8. Results of the Simulators (“Omnium Rerum, Vitiosa Est Simulatio”… Cicero) • The interaction of different fluids, plus “active” energy equation, leads to lognormal density distributions • Examples: converging WNM flows, evaporation fronts between WNM and CNM • Converging flows provide ram pressure as relevant normalizing pressure

  9. Admonition to Participants • Pay attention to Ellen Zweibel and Alex Lazarian. There are real questions on how you describe a magnetized plasma. Many scales in space and frequency. Most theoretical work has been directed by solar wind turbulence at 1au, which might be misleadingly simple compared to the ISM

  10. Ideas for the future Question: are the results from thermal equilibrium (different phases) relevant or irrelevant?

  11. Future Ideas (cont.) • I would like to see analysis of IDV to constrain Vprop relative to VA. . • This has been an important constraint in the case of the solar corona (Harmon-Coles 2005)

  12. Future Advances • COS upgrade to HST, higher density of optical lines of sight (Dave Meyer) • Radio Astronomy: higher density of lines of sight…EVLA and SKA • Theory: fundamental studies of transport coefficients (thermal conductivity, viscosity, etc) • Simulators should quantify how much overpressure they can furnish • Observers should “get sophisticated”, try and devise schemes for detecting vortices, etc

More Related