Electron and ion density depletions measured in the STS-3 orbiter wake

The third Space Shuttle flight on Columbia carried instrumentation to measure thermal plasma density and temperature. Two separate investigations, the Plasma Diagnostics Package (PDP) and the Vehicle Charging and Potential Experiment (VCAP), carried a Langmuir Probe, and the VCAP also included a Spherical Retarding Potential Analyzer (SRPA). Only those measurements made while the PDP is in the payload bay are discussed here since the VCAP instrumentation remains in the payload bay at all times and the two measurements are compared. The wake behind a large structure (in this case the Space Shuttle Orbiter) flying through the ionospheric plasma is discussed. Much theoretical work was done regarding plasma wakes. The instrumentation on this mission gives the first data taken with a large vehicle in the ionospheric laboratory. First, the PDP Langmuir Probe and its data set will be presented, then the VCAP Langmuir Probe and SRPA with associated data. The agreement between the two data sets is discussed and then followed by some other PDP data which infers an even lower wake density

Parametric Forcing of Waves with Non-Monotonic Dispersion Relation: Domain Structures in Ferrofluids?

Surface waves on ferrofluids exposed to a dc-magnetic field exhibit a non-monotonic dispersion relation. The effect of a parametric driving on such waves is studied within suitable coupled Ginzburg-Landau equations. Due to the non-monotonicity the neutral curve for the excitation of standing waves can have up to three minima. The stability of the waves with respect to long-wave perturbations is determined $via$ a phase-diffusion equation. It shows that the band of stable wave numbers can split up into two or three sub-bands. The resulting competition between the wave numbers corresponding to the respective sub-bands leads quite naturally to patterns consisting of multiple domains of standing waves which differ in their wave number. The coarsening dynamics of such domain structures is addressed.Comment: 23 pages, 6 postscript figures, composed using RevTeX. Submitted to PR

Rapid sequence induction: where did the consensus go?

Background Rapid Sequence Induction (RSI) was introduced to minimise the risk of aspiration of gastric contents during emergency tracheal intubation. It consisted of induction with the use of thiopentone and suxamethonium with the application of cricoid pressure. This narrative review describes how traditional RSI has been modified in the UK and elsewhere, aiming to deliver safe and effective emergency anaesthesia outside the operating room environment. Most of the key aspects of traditional RSI – training, technique, drugs and equipment have been challenged and often significantly changed since the procedure was first described. Alterations have been made to improve the safety and quality of the intervention while retaining the principles of rapidly securing a definitive airway and avoiding gastric aspiration. RSI is no longer achieved by an anaesthetist alone and can be delivered safely in a variety of settings, including in the pre-hospital environment. Conclusion The conduct of RSI in current emergency practice is far removed from the original descriptions of the procedure. Despite this, the principles – rapid delivery of a definitive airway and avoiding aspiration, are still highly relevant and the indications for RSI remain relatively unchanged

Phase Diffusion in Localized Spatio-Temporal Amplitude Chaos

We present numerical simulations of coupled Ginzburg-Landau equations describing parametrically excited waves which reveal persistent dynamics due to the occurrence of phase slips in sequential pairs, with the second phase slip quickly following and negating the first. Of particular interest are solutions where these double phase slips occur irregularly in space and time within a spatially localized region. An effective phase diffusion equation utilizing the long term phase conservation of the solution explains the localization of this new form of amplitude chaos.Comment: 4 pages incl. 5 figures uucompresse

TSS-1 - Orbiter current and voltage experiments

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76697/1/AIAA-1993-702-280.pd

Super-lattice, rhombus, square, and hexagonal standing waves in magnetically driven ferrofluid surface

Standing wave patterns that arise on the surface of ferrofluids by (single frequency) parametric forcing with an ac magnetic field are investigated experimentally. Depending on the frequency and amplitude of the forcing, the system exhibits various patterns including a superlattice and subharmonic rhombuses as well as conventional harmonic hexagons and subharmonic squares. The superlattice arises in a bicritical situation where harmonic and subharmonic modes collide. The rhombic pattern arises due to the non-monotonic dispersion relation of a ferrofluid

The current‐voltage characteristics of a large probe in low Earth orbit: TSS‐1R results

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95277/1/grl10536.pd

Shuttle charging by fixed energy beam emissions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95359/1/grl10599.pd

Current collection at the shuttle orbiter during TSS‐1R high voltage charging

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95673/1/grl10526.pd

Recent experimental measurements of space platform charging at LEO altitudes

The estimation of the extent of electrical charging of space platforms at low earth orbit (LEO) altitudes has been a subject of interest for a number of years. Early estimates based on theoretical current-voltage relationships of Langmuir and Blodgett and Parker and Murphy predicted a wide range of possible electrical potentials for a platform being actively charged at LEO altitudes. The experimental success of early electron beam experiments suggested that the early theories were incomplete. This has led to the development of space experiments specifically designed to study the degree of electrical charging resulting from electron beam emission, and also supplementary experiments to determine the current voltage relationship of large structures biassed to high voltages in the LEO environment. The paper will discuss some of the results of vehicle electrical potential from recent sounding rocket experiments involving charging of a space platform by both electron beam emission, and by the application of differential bias between elements of the platform.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29690/1/0000021.pd