TY - GEN
T1 - Plasma-like "sausage" oscillations in astrophysical disks
AU - Griv, Evgeny
PY - 2012/12/1
Y1 - 2012/12/1
N2 - Most rotating astrophysical disks ranging from planetary rings to galaxies display graceful spiral (and circular) patterns. Yet, over almost 240 years after their first discovery in galaxies by Charles Messier in 1773, we still do not fully understand how they originate. In this paper, a modified theory of the Lin-Shu density waves (or "heavy sound") is presented in which both the axisymmetric and nonaxisymmetric structures of astrophysical disks arise from the classical Jeans compression-type instability of small gravity perturbations (e.g. those produced by a spontaneous disturbance). A method is given for the analytical solution of the self-consistent system of the gasdynamic equations and the Poisson equation describing the stability of a given three-dimensional disk composed of gravitating particles, stars, or gaseous clouds. The obtained results for these unstable (that is to say, amplitude growing) even-parity "sausage" oscillations may be applicable to such phenomena as the appearance of the in-plane circular and/or spiral structures of various astrophysical disks. In neutral plasmas such stable collective oscillations correspond to the electrostatic plasma oscillations propagating in a free electron gas, also known as "Langmuir waves".
AB - Most rotating astrophysical disks ranging from planetary rings to galaxies display graceful spiral (and circular) patterns. Yet, over almost 240 years after their first discovery in galaxies by Charles Messier in 1773, we still do not fully understand how they originate. In this paper, a modified theory of the Lin-Shu density waves (or "heavy sound") is presented in which both the axisymmetric and nonaxisymmetric structures of astrophysical disks arise from the classical Jeans compression-type instability of small gravity perturbations (e.g. those produced by a spontaneous disturbance). A method is given for the analytical solution of the self-consistent system of the gasdynamic equations and the Poisson equation describing the stability of a given three-dimensional disk composed of gravitating particles, stars, or gaseous clouds. The obtained results for these unstable (that is to say, amplitude growing) even-parity "sausage" oscillations may be applicable to such phenomena as the appearance of the in-plane circular and/or spiral structures of various astrophysical disks. In neutral plasmas such stable collective oscillations correspond to the electrostatic plasma oscillations propagating in a free electron gas, also known as "Langmuir waves".
KW - Milky Way
KW - Oscillations
KW - Plasma waves
KW - Saturn's rings
KW - Self-gravitating systems
UR - http://www.scopus.com/inward/record.url?scp=84886045146&partnerID=8YFLogxK
U2 - 10.1063/1.3701358
DO - 10.1063/1.3701358
M3 - Conference contribution
AN - SCOPUS:84886045146
SN - 9780735410312
T3 - AIP Conference Proceedings
SP - 154
EP - 171
BT - Waves and Instabilities in Space and Astrophysical Plasmas
T2 - Workshop on Waves and Instabilities in Space and Astrophysical Plasmas
Y2 - 19 June 2011 through 24 June 2011
ER -