9939(  1) - 04/04/03 10:25  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9939
                                                       Version: 1
                                                       Check-in Date: 04-Apr-2003
                                                                      10:25:35

1.Proposal Title:
Flows, Turbulence, and Mixing
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2. Proposal For  3. Cycle
AR               11
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4. Investigators
                                                                                     Contact?
    PI: Alex Lazarian                     University of Wisconsin - Madison
   CoI: Dr. Robert Benjamin               University of Wisconsin - Madison             N
   CoI: Dr. Jungyeon Cho                  University of Wisconsin - Madison             N
   CoI: Dr. John Mathis                   University of Wisconsin - Madison             N

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5. Abstract

HST and FUSE spectra of distant UV-bright sources reveal interstellar absorption
lines of high stages of ionization (O VI, C IV, N V, Si IV) arising in many
different astrophysical environments such as superbubbles, interstellar chimneys,
high-velocity clouds, galaxy halos and cosmic filaments. Turbulence, always present
in the magnetized ISM, must mix the hot (~10^6 K) gas with cooler gas within
"turbulent mixing layers". Present theory, based on 1D steady-state flows, suggest
the line ratios in these layers differ significantly from photoionized gas,
radiative shocks, cooling zones, or conduction fronts. These models are use to infer
mass and energy fluxes important to understanding the ISM. We propose to develop a
suite of 3D time-dependent models that properly calculate turbulent mixing. We will
produce synthetic UV absorption lines and optical emission lines directly relevant
to HST observations that use GHRS, STIS, and eventually, COS. These models will
allow us to explore the sensitivity of the spectral diagnostics to magnetic field
strength, turbulence intensity, and relative velocity of the hot and cold gas. We
will publish the resulting grid of spectral diagnostics and make them available
through the Web.
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                                                9939(  1) - 04/04/03 10:25  - [  2]

            Summary Form for Proposal  9939

  Item                         Used in this proposal
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  Proposal Category            AR
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