Critical Velocity Effect Research Articles

A 1972 prediction of Uranian rings based on the Alfv�n critical velocity effect

A 1972 prediction of Uranian rings based on the Alfv�n critical velocity effect

Interstellar clouds and the formation of stars

Part I gives a survey of the drastic revision of cosmic plasma physics which is precipitated by the exploration of the magnetosphere throughin situ measurements. The ‘pseudo-plasma formalism’, which until now has almost completely dominated theoretical astrophysics, must be replaced by an experimentally based approach involving the introduction of a number of neglected plasma phenomena, such as electric double layers, critical velocity, and pinch effect. The general belief that star light is the main ionizer is shown to be doubtful; hydromagnetic conversion of gravitational and kinetic energy may often be much more important. In Part II the revised plasma physics is applied to dark clouds and star formation. Magnetic fields do not necessarily counteract the contraction of a cloud; they may just as well ‘pinch’ the cloud. Magnetic compression may be the main mechanism for forming interstellar clouds and keeping them together. Part III treats the formation of stars in a dusty cosmic plasma cloud. Star formation is due to an instability, but it is very unlikely that it has anything to do with the Jeans instability. A reasonable mechanism is that the sedimentation of ‘dust’ (including solid bodies of different size) is triggering off a gravitationally assisted accretion. A ‘stellesimal’ accretion analogous to the planetesimal accretion leads to the formation of a star surrounded by a very low density hollow in the cloud. Matter falling in from the cloud towards the star is the raw material for the formation of planets and satellites. The study of the evolution of a dark cloud leads to a scenario of planet formation which is reconcilable with the results obtained from studies based on solar system data. This means that the new approach to cosmical plasma physics discussed in Part I logically leads to a consistent picture of the evolution of dark clouds and the formation of solar systems.

Non-linear vibration of a traveling threadline

The motion of a moving threadline under planar periodic boundary excitation is examined. Equations of motion are formulated and include the variables of displacement, velocity, tension and mass. Two exact solutions of the non-linear system are developed. Numerical solutions of simplified models predict instabilities of a hard spring nature. Experiments show that the plane motion is truly non-linear and does have a hard spring jump that is basically a critical velocity effect. Additionally a three dimensional balloon occurs which also shows a jump of a completely different character.