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Interstellar Medium Around Sol / Interstellar Ramscoop

  1. Jul 4, 2012 #1
    So, I've read here http://en.wikipedia.org/wiki/Interstellar_medium that the Interstellar medium varies greatly throughout space.

    Of the categories listed; Molecular clouds, Warm Neutral Medium, Clound Neutral Medium, Warm Ionized Medium, H II regions, and Coronal Gas/Hot Ionized Medium, which best describes the area around our solar system?

    I'm designing an interstellar Ramjet-Augmented Interstellar Ramscoop for some fiction, so it'd be nice to know if the space around the solar system is ionized or not, since I'd consider a magnet-based collector more or less a necessity in design.

    If it's not, then what kind of battery of lasers would be needed to ionize the hydrogen in-between here and Tau Ceti? (12 LY appx.)
  2. jcsd
  3. Jul 5, 2012 #2


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  4. Jul 5, 2012 #3
    You may have a problem with a ram-scoop near us due to the 'Local Bubble'.

    This 'too thin to scoop' zone may, incidentally, provide a plausible answer to 'Where Are They' for ET limited to c...
  5. Jul 5, 2012 #4
    Well the local interstellar cloud is a good bit thicker...

    Seems like at 6,000 *K hydrogen would have to be ionized. Atoms ionize when they have a certain amount of energy, right? So wouldn't that correspond to a certain temperature?
  6. Jul 5, 2012 #5


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    NASA is using the term VLISM (very local interstellar medium) to describe what our heliosphere is currently interacting with. It turns out there is unexpected structure, emissions and physics in the new observations. In situ measurements with new hardware will be required to answer the many puzzles, they say.

    The ongoing Voyager Interstellar Mission (VIM) and recent observations from the Interstellar Boundary Explorer (IBEX) and Cassini missions are providing significant new information about the interaction of the heliosphere with the very local interstellar medium (VLISM). With new observations have come significant new puzzles for describing the interaction physics. Direct measurements of the shocked, solar-wind flow speed are now possible (from Voyager 2) and show the flow remains supersonic. This is one more piece of evidence supporting the idea that the bulk of the energy density in the plasma resides in a non-thermal component that extends to very high energies. There are both quantitative and qualitative implications for the overall heliospheric structure. Observations of energetic neutral atoms (ENAs) by IBEX (in Earth orbit) from the interaction region(s) of the solar wind and the VLISM show unexpected structure on a variety of scales. In addition to the general “glow” of the sky in ENAs, IBEX data show a relatively narrow “ribbon” of atomic hydrogen emission from ∼200 to ∼6 keV, roughly circular, but asymmetric in intensity, and centered on an ecliptic longitude ∼221 degrees and ecliptic latitude of 39 degrees. The ribbon may be ordered by the interstellar magnetic field. It passes through, rather than being centered on, the “nose” from which the local, neutral interstellar wind enters the Heliosphere, indicating that the flow is not the primary driver of the system as had been thought previously. The neutrals from both the glow and ribbon are also characterized by non-thermal distribution functions. ENAs are observed at higher energies as well by the Ion and Neutral Camera (INCA) on Cassini (in orbit about Saturn). A “belt” of emission, broader than the ribbon but similar to it, is seen up to ∼50 keV. These observations emphasize the need for in situ measurements to understand the global nature of our local galactic environment, which is much more complex than previously thought. Only an interstellar probe with modern instruments and measurement requirements better defined by these recent observations can provide the new information required.

    Respectfully submitted,
  7. Jul 5, 2012 #6
  8. Jul 6, 2012 #7
    Assume it's ionized and you won't be too far wrong. But, as the other replies have noted, the LISM is under-dense compared to the average stretch of our Galaxy. Thin feed for a ramjet. How are you powering it BTW? I'm with "Project Icarus" and RAIR designs are one of my areas of research.
  9. Jul 22, 2012 #8
    I am curious to know how large the collector is. Fiction author Larry Niven's "ramships" had pretty large funnel-shaped magnetic fields (1 million KM - too long since I read them?)
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