Para hydrogen equilibration in the atmospheres of the outer planets

The thermodynamic behavior of the atmospheres of the Jovian planets is strongly dependent on the extent to which local thermal equilibration of the ortho and para states of molecular hydrogen is achieved. Voyager IRIS data from Jupiter imply substantial departures of the para hydrogen fraction from equilibrium in the upper troposphere at low latitudes, but with values approaching equilibrium at higher latitudes. Data from Saturn are less sensitive to the orth-para ratio, but suggest para hydrogen fractions near the equilibrium value. Above approximately the 200 K temperature level, para hydrogen conversion can enhance the efficiency of convection, resulting in a substantial increase in overturning times on all of the outer planets. Currently available data cannot definitively establish the ortho-para ratios in the atmospheres of Uranus and Neptune, but suggest values closer to local equilibrium than to the 3.1 normal ratio. Modeling of sub-millimeter wavelength measurements of these planets suggest thermal structures with frozen equilibrium lapse rates in their convective regions

Influence of planetary-scale topography on the diurnal thermal tide during the 1971 Martian dust storm

Data obtained with the Mariner 9 infrared spectroscopy experiment during the Martian Dust Storm of 1971 to 1972 are examined for evidence of topographic influence on the atmospheric thermal structure. Temperature perturbations which are well correlated with the planetary scale topography are found superposed on the large amplitude diurnal thermal tide. Applications of tidal theory to the data indicate that the observed perturbations result from the kinematic interaction of the westward traveling diurnal wave with the large scale components of topography. The dominant mode is excited by the wave-number two topography component and is a vertically evanescent eastward traveling wave with an equivalent depth comparable to the atmospheric scale height. The principle dynamic effect of this mode is the enhancement of the amplitude of the near-surface diurnal wind to over 40m/sec in limited areas near 30 deg south latitude. It appears likely that dust was injected into the atmosphere in these regions during the storm

Dynamics of the atmospheres of the outer planets

Current knowledge about dynamics and the thermal structure of the outer planets is reviewed with the aim of identifying important measurements which should be made in the post-Voyager era. The existence of jets and cloud bands is the puzzle that underlies all others. The discussion focuses on the particular case of Jupiter because the documentation is the most complete. It is argued that the gross dynamical parameters of the outer planetary atmospheres are the keys to their behaviors, rather than the particular specifics of radiative forcing, cloud distributions, or thermodynamic transformations. Voyager data has shown that the jet systems decay with height in the region above the visible clouds. Therefore, the highest priority must be given to establishing dynamical parameters that characterize levels within and beneath the clouds. These require the determination of the deep structure of the jets, of the density stratification, and of the horizontal density contrasts. The deep regions are not easily accessible and these measurements present challenging opportunities. Indirect inferences about the controlling processes may sometimes be possible by observing waves and other activity in the more easily accessible stratosphere

Dynamics of Liquid Metal Drops Influenced by Electromagnetic Fields

Zusammenfassung Diese Arbeit ist den Effekten gewidmet, die an der Oberfläche von Flüssigmetall im Magnetfeld auftreten können. Im Prinzip erlauben Magnetfelder, Lorentzkräfte auf flüssiges Metall auszuüben und in seinem Innern Induktionswärme zu generieren. Es ist aber auch bekannt, dass Flüssigmetall-Oberflächen durch Magnetfelder dramatische Formänderungen oder Schwingungen erfahren können. Ein Verständnis dieser Phänomene ist wichtig für sämtliche metallurgische Anwendungen, bei denen freie Oberflächen vorkommen. Als repräsentatives Problem untersuchen wir einen Tropfen aus Flüssigmetall, der eine freie Oberfläche mit einem endlichen Volumen verbindet. Wir schliessen Temperatureffekte aus und konzentrieren uns auf die Wirkung der Lorentzkraft. Wir erarbeiten ein Schema zur Klassifikation von Tropfen-Magnetfeld-Problemen basierend auf der Frequenz des Magnetfeldes und dem Shielding-Parameter des Tropfens in diesem Feld. Anhand dieses Schemas wählen wir fünf Fallstudien aus und studieren das Tropfenverhalten im i) transienten, ii) hochfrequenten und iii) mittelfrequenten Magnetfeld. Die Untersuchungen sind vorwiegend analytischer Art, nur die Mittelfrequenz-Studie ist experimentell. Die beiden wichtigsten Probleme, welche die vorliegende Arbeit zum Gegenstand hat, sind das symmetrische Zusammendrücken oder Halten von Flüssigmetalltropfen einerseits und deren azimutale Verformungen andererseits. Für das transiente Magnetfeld werden zwei Studien präsentiert, jede zu einem der beiden Hauptprobleme. Eine Verbindung zwischen transientem und hochfrequentem Feld besteht darin, das mit beiden Feldtypen stationäre Kräfte im Metall erzeugt werden können. Ein wichtiger Unterschied ist jedoch, dass transiente Felder das Metall durchdringen können, während hochfrequente Felder vom Metall abgeschirmt werden, wodurch eine Kopplung zwischen Tropfenform und Magnetfeld entsteht. Die Effekte im hochfrequenten Feld sind daher schwieriger zu modellieren. Wir präsentieren eine Hochfrequenz-Studie, in der es um das Zusammendrücken und Halten von Tropfen in einem gegebenen Magnetfeld geht. Eine zweite Hochfrequenz-Studie beschäftigt sich mit longitudinaler Levitation. Dort geben wir als einfache Tropfenform einen Flüssigmetall-Zylinder vor und ermitteln das Magnetfeld, welches die vorausgesetzte Tropfenform tatsächlich ermöglichen würde. Im mittelfrequenten Feld bieten sich für theoretische Betrachtungen die grössten Schwierigkeiten, da das Magnetfeld den Tropfen nun partiell durchdringt und kaum noch vereinfacht werden kann. Dieser Bereich wurde daher durch die fünfte Studie experimentell erkundet. Dabei wurde eine Flüssigmetall-Scheibe verwendet, welche nur zweidimensionale Verformungen ausführen kann. Die Ergebnisse der Arbeit zeigen, dass insbesondere transiente Magnetfelder gangbare Wege der analytischen Modellierung bieten. Ebenso wie hochfrequente Magnetfelder eignen sie sich zum Formen und Stützen freier Flüssigmetall-Oberflächen. Für das Studium der azimutalen Verformungen hat sich die Scheiben-Geometrie als günstig erwiesen, sowohl analytisch als auch experimentell. Insgesamt zeigt sich, dass eine Fortführung der Arbeit auf dem Gebiet der Wechselwirkung zwischen Magnetfeldern und Flüssigmetall-Oberflächen lohnenswert ist.This work is devoted to the free surface effects that occur when liquid metal is placed in a magnetic field. Principally, magnetic fields allow to exert Lorentz forces on liquid metal and to generate induction heat inside it. But it is also known that liquid metal surfaces in magnetic fields can undergo dramatic shape changes or experience oscillations. An understanding of these phenomena is crucial to all metallurgical applications showing free surfaces. As a representative problem we examine a liquid metal drop that combines a free surface with a finite volume. We exclude heat effects and focus on the consequences of the Lorentz force. To this end, we elaborate a classification scheme for liquid metal drop - magnetic field problems comprising the frequency of the magnetic field and the Shielding parameter of the drop in this field. On that basis we select five case studies involving i) transient, ii) middle-frequency and iii) high-frequency magnetic field to explore the behavior of liquid metal drops in it. We mainly use analytical means - only the middle-frequency study is experimental. The major problems we tackle concern the symmetric squeezing and supporting of drops and its azimuthal deformations, respectively. Two studies are presented for the transient magnetic field, each accounting for one of the two problems. A connection between transient and high frequency magnetic field is the possibility to exert a steady force on the liquid metal. An important difference is that transient fields can penetrate the metal while high-frequent fields are shielded by the metal resulting in a coupling between surface shape and magnetic field distribution. Therefore, the effects of high frequency magnetic fields are more difficult to model. We present one high frequency study where we presuppose the magnetic field and ask for the resulting drop shape (forward problem) and another one where we presuppose a simple surface shape and ask for the best suited magnetic field to obtain it (reverse problem). The most difficulties arise in middle-frequent magnetic fields. Here we have partial shielding which makes it necessary to solve the magnetic diffusion equation and to account for the coupling between magnetic field and drop surface at the same time. In this field, the fifth study reports experimental results on the azimuthal deformations of a liquid metal disc in an inhomogeneous inductor field. The results of the work show that especially the transient fields provide feasible ways for analytical modeling. Like high frequency fields they are suited to shape and to support liquid metal surfaces. To study azimuthal deformations, the disc geometry has proven useful - both analytically and experimentally. Overall, it still seems worthwhile to further investigate the behavior liquid metal surfaces in magnetic fields

Superrotation planetary atmospheres: Mechanical analogy, angular momentum budget and simulation of the spin up process

Superrotation rates observed in planetary atmospheres are analyzed based on the concept of a thermally driven zonally symmetric circulation. Specifically, how this superrotation is produced and maintained against the tendency for friction to oppose differential motions between the atmosphere and the underlying planet is addressed. The time evolution of a fluid leading from corotation under uniform heating to superrotation under globally nonuniform heating is simulated using a three dimensional zonally symmetric spectral model and Laplace transformation. The increased tendency toward geostrophy combined with the increase of surface pressure toward the poles (due to meridional mass transport), induces the atmosphere to subrotate temporarily at lower altitudes. The resulting viscous shear near the surface thus permits angular momentum to flow from the planet into the atmosphere where it propagates upwards and, combined with the change in moment of inertia, produces large superrotation rates at higher viscosities

the role of emotion regulation in the defensive processing of fear-arousing health-risk information

Individuals often respond defensively to emotive fear appeals that target people\u27s unhealthy behaviors and aim to instill motivation for behavioral change. Both classic and contemporary models of defensiveness assume that these defensive reactions allow people to down-regulate the negative emotional experience resulting from the fear appeals (i.e., to feel better about their unhealthy behavior). However, no study to date has directly examined emotional regulatory processes, such as cognitive reappraisal, that may occur during fear appeals. In the present study, female participants\u27 caffeine use and self-rated cancer risk were measured before they viewed a health message about a link between caffeine and ovarian cancer. Implicit state affect was measured during and after the message, and then participants rated their acceptance of the message and their own cancer risk again. Trait reappraisal interacted with reported caffeine use to predict less message acceptance. Evidence for the role of affect in defensiveness was not found

Nursery delineation, movement patterns, and migration of the sandbar shark, Carcharhinus plumbeus, in the eastern shore of Virginia coastal bays and lagoons

The identification and delineation of nursery areas and areas of aggregation of north Atlantic sharks has been identified as an important information need for future management efforts. The objectives of this project were to use a fishery-independent method to study the overwintering area of juvenile sandbar sharks, to spatially delineate the Eastern Shore nursery area, and to examine movement patterns and space use within this nursery area. Data from 21 satellite transmitters attached to large juvenile sandbar sharks revealed that these sharks primarily occurred off the outer banks of North Carolina, at deeper depths and colder water temperatures during the overwintering period (after November 1). The data from this project support the size and scope of the closed area currently enacted by the Fishery Management Plan. The Eastern Shore of Virginia was found to be an important primary and secondary nursery area for this population of sandbar sharks. Within this nursery area sharks were most concentrated in Great Machipongo Inlet. Abundance of juvenile sandbar sharks was positively correlated to distance from the inlet and water temperature. Smaller juvenile sharks were more concentrated farther from the inlets and were more prevalent in the southern inlets. Juvenile sandbar shark movements were studied using passive acoustic telemetry. Juveniles tended to spend significantly more time farther from the inlets and their space use was positively correlated to time of day with a greater proportion of time spent in the acoustic array during the night time hours. Tidal currents were positively correlated with small scale movements but were unrelated to overall space use. The sharks tracked returned or remained within the array to a greater extent than would be predicted by random movements alone indicating these animals have some site attachment to these areas. Smaller sharks remained within the array area to a greater extent than larger sharks indicating they likely have smaller activity spaces. This study emphasizes the importance of both the Eastern Shore of Virginia nursery area and the overwintering area that occurs off the central coast of North Carolina as essential habitat for the north Atlantic population of sandbar sharks

Violation of the Second and Third Adiabatic Invariants by Hydromagnetic Waves

Investigation of hydromagnetic waves which violate adiabatic invariants of geomagnetically trapped charged particle motio