Acoustic Instabilities in Nonadiabatic Weakly Ionized Gases with Applied Magnetic Fields

AIAA Journal ◽  
1977 ◽  
Vol 15 (8) ◽  
pp. 1208-1210 ◽  
Author(s):  
D. Bastos-Netto ◽  
D. N. Nobre ◽  
J. P. Sudano
Keyword(s):  
Magnetic Fields ◽  
Weakly Ionized ◽  
Acoustic Instabilities

AMBIPOLAR DIFFUSION AND TURBULENT MAGNETIC FIELDS IN MOLECULAR CLOUDS

2011 ◽  
Vol 26 (04) ◽  
pp. 235-249 ◽  
Author(s):  
MARTIN HOUDE ◽  
TALAYEH HEZAREH ◽  
HUA-BAI LI ◽  
THOMAS G. PHILLIPS
Keyword(s):  
Magnetic Fields ◽  
Molecular Clouds ◽  
Ambipolar Diffusion ◽  
Star Forming ◽  
Star Forming Regions ◽  
Spin Interactions ◽  
Line Narrowing ◽  
Weakly Ionized ◽  
Novel Method

We review the introduction and development of a novel method for the characterization of magnetic fields in star-forming regions. The technique is based on the comparison of spectral line profiles from coexistent neutral and ion molecular species commonly detected in molecular clouds, sites of star formation. Unlike other methods used to study magnetic fields in the cold interstellar medium, this ion/neutral technique is not based on spin interactions with the field. Instead, it relies on and takes advantage of the strong cyclotron coupling between the ions and magnetic fields, thus exposing what is probably the clearest observational manifestation of magnetic fields in the cold, weakly ionized gas that characterizes the interior of molecular clouds. We will show how recent development and modeling of the ensuing ion line narrowing effect leads to a determination of the ambipolar diffusion scale involving the turbulent component of magnetic fields in star-forming regions, as well as the strength of the ordered component of the magnetic field.

scholarly journals Turbulent Diffusion of Magnetic Fields in Weakly Ionized Gas

2002 ◽  
Vol 578 (2) ◽  
pp. L113-L116 ◽  
Author(s):  
Eun-jin Kim ◽  
P. H. Diamond
Keyword(s):  
Magnetic Fields ◽  
Turbulent Diffusion ◽  
Ionized Gas ◽  
Weakly Ionized

A Study of a Weakly Ionized Rotating Plasma

1979 ◽  
Vol 34 (6) ◽  
pp. 672-690 ◽  
Author(s):  
M. M. B. Wijnakker ◽  
E. H. A. Granneman ◽  
J. Kistemaker
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Pressure Distribution ◽  
Rotational Velocity ◽  
Symmetry Plane ◽  
Radial Pressure ◽  
Plasma Potential ◽  
Theoretical Treatment ◽  
Ion Temperature ◽  
Weakly Ionized

Abstract Measurements are reported on a weakly ionized rotating argon plasma generated by two identical gas discharges facing each other. In each discharge a current up to 100 A is drawn between a point-like cathode and a ring-shaped anode. Axial magnetic fields up to 0.26 T are applied. All measurements have been done at 1 torr.For magnetic field strengths below 0.17 T the plasma has a more or less uniform radial distribution; above 0.17 T a contracted plasma column is present along the axis of the cylinder. In the symmetry plane between the two discharges measurements have been done on the rotational velocity of neutrals and ions, the electron density and temperature, the ion temperature, the plasma potential and the radial pressure distribution. The rotational velocity, the plasma potential and the pressure distribution are also calculated. The theoretical treatment is based on the theory developed by Klüber and Wilhelm and Hong.In the low magnetic field case velocities of 700 m/sec are found for ions as well as neutrals. The agreement between theory and experiment is good in this case. At high magnetic fields, the ions and neutrals are found to have azimuthal velocities of 1900 and 700 m/sec, respectively.The radial pressure enhancement due to the centrifugal forces is found to be approximately a factor of two whereas the theory predicts only a factor of 1.2. In a discharge in which a mixture of argon and xenon is used a relative separation factor of 2.15 is found.

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