A 1972 prediction of Uranian rings based on the Alfvén critical velocity effect

It is speculated from an empirical point of view that there may be yet unobserved matter around the planet Uranus inside the orbit of Miranda. Such matter, if any, is likely to be emplaced in the form of rings.In December, 1972, this paper — exactly as it is presented here, but with the title On the Posibility of Existence of a Ring of Uranus-was submitted to another scientific journal in the relevant field and was rejected. After the discovery of the Uranian rings, the same journal was requested to reopen the question of publication. This was done, and the paper was again rejected. The author has providedThe Moon and the Planets with proof of the original submission.Paper dedicated to Professor Hannes Alfvén on the occasion of his 70th birthday, 30 May 1978.     

Criterion for propagation of magnetohydrodynamic waves: An equivalence

It is shown that the requirement that a magnetohydrodynamic wave propagate over a distance equal to a large number of wavelengths without substantial attenuation is equivalent to the requirement that the lateral velocity of displacement of the field lines far exceed a characteristic velocity. This latter velocity is the velocity of slippage of the field lines with respect to the medium.     

Hydromagnetic interaction in a fluid dielectric

It is shown that a dielectric fluid is capable of hydromagnetic interaction, much like a conducting fluid. The physical principle of this interaction is outlined and the criteria for dominance of the interaction are derived.     

Petrology and geochemistry of mafic dykes of Sylhet traps,Northeastern India,and their Kerguelen plume linkage

Mineralogy and Petrology - We present here a new set of mineralogical and geochemical data from a cluster of east southeast-trending mafic dykes that intrude a lava flow of Sylhet traps. These...     

The dielectric analogue of magnetohydrodynamics

Almost half a century after Alfvén first conceived of the science of magnetohydrodynamics, it is still possible to trace his intuitive thinking to explore physical processes heretofore not considered. The ideas of magnetohydrodynamics (applicable to conducting fluids) can be transferred almost intact to purely dielectric fluids, such that we can arrive at a generalized concept applicable toany fluid-conducting or dielectric. In this sense, Alfvén's conception of magnetohydrodynamics may be ideationally even more profound than it has been thought to be so far.Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988.     

On the mechanism of formation of loop prominences

A mechanism is suggested for the formation of loop-type prominences in solar-active regions following flare events. The mechanism is based on the already existing idea of compression of a coronal plasma element resulting in enhanced radiation and consequent cooling of the element. A model is suggested for such a compression based on the concept of a contracting, force-free filamentary structure. If the current in a filament increases with time, then there is a radial contraction of the filament. Since the coronal plasma is frozen into the magnetic field lines of the filament, a contraction of the filament causes a compression of the filamentary plasma. This model of compression is shown to be in approximate qualitative and quantitative agreement with observations.     

Disequilibrium condensation environments in space: A frontier in thermodynamics

Quasi-steady states with a disequilibrium between the gas phase kinetic temperature and the condensed phase internal temperature appear to be the norm of condensation environments in space. Such states may constitute Prigogine dissipative structures.Invited contribution to the Proceedings of a Workshop onThermodynamics and Kinetics of Dust Formation in the Space Medium held at the Lunar and Planetary Institute, Houston, 6–8 September, 1978.     

Surface density of accumulated electrons on walls in contact with a plasma

It is shown that the surface density of accumulated electrons on a wall in contact with a plasma can be expressed as a simple function of the Debye shielding distance in the plasma. The result may have applications to problems involving objects immersed in a space plasma.     

Lava channel of Khedrai Dam,northeast of nasik in western Deccan Volcanic province: Detailed morphology and evidences of channel reactivation

The 120 m-wide Khedrai Dam lava channel is one of the widest recorded in the Deccan Volcanic Province. Like many recent ones, this channel also has a pair of linear marginal levees made of breccia and confines the channelfill lava. It is resting over a pahoehoe flow (substrate) of basalt studded with plagioclase megacrysts, also known as the Giant Plagioclase Basalt (GPB). The channel-fill lava, which makes the lining at the edges and basal portion of the channel, is a comb-layered basalt (Cl-B) characterized by alternating layers rich in curved, branching augite crystals and laths of plagioclase — a texture indicative of high order of supercooling and rapid cooling rates. The dominant and centrally filling lava of this channel is a plagioclase-phyric basalt (Pp-B) that has a wide variation in phenocryst number from megacryst-poor to megacryst-rich. Occurrence of centimetre to decimetre size angular fragments of Cl-B within Pp-B fill indicates mechanical dislodgements of channel-lining by flowing lava. This also suggests that the channel was reactivated before it finally lost its hydraulic gradient and solidified.