The School offers a number of research areas for postgraduate students interested in continuing studies in Mathematics and Physics.

The main areas of research are:

• Atomic and Molecular Physics
• Computational and Applied Mathematics
• Fluid Dynamics, Oceanography and Meteorology
• Statistics and Intelligent Data Analysis
• Biomechanics

Collisions of trapped metastable helium atoms
I.B. Whittingham
  As a result of significant interest by major overseas experimental groups in our recently completed calculations, it is proposed to undertake further precise quantum-mechanical calculations of collisions involving ultracold metastable helium atoms confined by magnetic and laser optical forces in atom traps. These calculations will produce predictions for collision rates and trap loss rates that should enable experimentalists to design improved atom traps. Atom traps are used to produce nearly stationary atoms and form the basis of new time and frequency standards and of the new technology of atom optics in which atomic beams replace laser beams.

Electron and ion transport in O2 and Ar/O2 magnetron discharges used in the manufacture of micreolectronic device favrication and thin film deposition
R.D. White
  The study of the processes involved in the manufacturing of computer chips is a priority area of research internationally. The aim of the project is to accurately model the transport properties of charged particles in magnetron discharges commonly used in the plasma processing of ultra-large- scale integrated circuits. The project aims to investigate and overcome many of the approximations presently associated with the modeling of this type of discharge. This project will foster the existing international links between JCU and Keio University, industrial links with Asahi Glass and further enhance JCU's reputation in the field of gaseous electronics.

Study of semi-classical and quantum effects in the analysis of swarm experiments and plasma discharges used in microelectronic device manufacture.
R.D. White, M. Steele, R.E. Robson
  The project addresses a long-standing controversy in the field of atomic and molecular physics - the magnitude of the vibrational cross-section in molecular hydrogen. The implications of this controversy however, extend far beyond the field of atomic and molecular physics e.g. doubt exists on the application of traditional kinetic theory methods to model devices such as plasma discharges used in microelectronic device fabrication. This project will explore various facets of the swarm experiment and its analysis including a study of error magnitudes in traditional kinetic theory, quantum degeneracy effects, and the move towards a new form of the collision operator.

Modelling of magnetron discharges used for microelectronic device fabrication
K.F. Ness, R.D. White
  The study of the processes involved in the manufacturing of computer chips is a priority area of research internationally. The aim of the project is to accurately model the transport properties of charged particles in magnetron discharges, discharges which are commonly used in the plasma processing of ultra large scale integrated circuits. The project aims to overcome the many approximations presently associated with the modeling of this type of discharge, achieving accuracy to within 0.5% in comparison with errors of the order of 5-20% presently obtained by other workers. This project will foster the international links which exist between JCU and Keio University. This project will enhance JCU’s reputation in the field of gaseous electronics. Outcomes include joint collaborative papers in international journals and computer packages which will enhance the consultancy capabilities of JCU in this field.

Theoretical study of ultracold collisions in trapped metastable rare gas atoms
I.B. Whittingham
  It is proposed to carry out precise quantum-mechanical calculations of collisions involving ultracold metastable helium, neon and argon atoms (temperatures of a few nanokelvin) confined by magnetic and laser optical forces in atom traps. These calculations will require the generation of new molecular potentials of very accurate long-range form to represent the interactions between these metastable atoms and will bring together all the major factors necessary to produce reliable predictions for the collision rates and trap loss rates. This should enable experimentalists to design improved atom traps and ultracold atom beams.

Collisions of magneto-optically trapped metastable helium atoms
I.B. Whittingham
  It is proposed to carry out precise quantum-mechanical calculations of collisions involving ultracold metastable helium atoms confined by magnetic and laser optical forces in atom traps. These calculations will require the generation of new molecular potentials to describe the laser excited molecular helium states and will produce predictions for collision rates and trap loss rates that should enable experimentalists to design improved atom traps. Atom traps are used to produce nearly stationary atoms and are essential to the new technology of atom optics in which atomic beams replace laser beams.

COMPUTATIONAL AND APPLIED MATHEMATICS

Large amplitude waves over multiple obstacles in two and three dimensions
S.R. Belward, W.W. Read
  The problem of fluid flow over obstacles has wide application in engineering and the physical sciences (e.g wind flowing over hills or water flowing around a ship’s hull). Often waves are generated in the fluid and when these are large they become difficult to calculate. Large amplitude waves over a single obstacle have been studied in depth over about the last fifteen years. In this project large amplitude waves over multiple obstacles will be considered. Waves behind two and three dimensional obstacles will be calculated.

The effects of ribbon reefs on the dynamical links between the Great Barrier Reef and the Coral Sea: initial model studies
L. Bode
  Modelling and field data suggest that hydrodynamic effects around ribbon reefs in the northern part of the Great Barrier Reef produce current patterns that increase the residence times of larvae and other organisms. This contrasts with the situation further south, where the poleward-flowing East Australian Current causes a nett southward movement of matter. This project aims to extend our existing numerical techniques for modeling the hydrodynamic effects of ribbon reef geometry, so that we can calculate more accurately the currents and transport patterns in this area of the continental shelf.

Accurate Solutions for Advection and Diffusion in Porous Media Using Orthogonal Coordinates
W.W. Read, G.E. Sneddon
  This project will develop accurate and efficient methods to quantify the transport of contaminants through groundwater systems. Previously, numerical methods used to analyse contaminant movement in saturated aquifers have suffered from effects such as numerical diffusion, where concentrations of contaminants are diffused by the numerical scheme instead of the underlying physical process. The solution methods that we will provide will eliminate or minimize these problems, so that the contamination of groundwater systems can be accurately modeled. In a country like Australia, that depends so heavily on primary industry and agriculture, a comprehensive knowledge and understanding of these processes is critical.

The laminations of the thixotropic diatom sediment of long pocket
P.V. Ridd, P.J. Stephenson, Raphael Wust
  Long Pocket, near Charters Towers is a small lake surrounded by lava flows. The sediment in the lake is composed of dead diatoms, small organisms. The sediment contains very fine scale laminations which are likely to provide a record of climatic conditions in the last 13000 years. These laminations are likely to be similar to tree rings. This project is designed to solve some of the problems with sampling the sediment that is thixotropic, i.e. it turns to fluid when it is vibrated. In addition it will attempt to determine the cause of the laminations.

Radio Wave Attenuation in Severe Atmospheric Conditions
M.L. Heron
  During extreme energetic events in the physical environment static electric charges are produced which can, theoretically, affect radio wave propagation. Such events are thunderstorms, squalls, tropical cyclones and bushfires. In this project we propose to evaluate the effect of bushfires on radio wave propagation and to search for a link between the temperature at the seat of the fire (which can be easily measured by infrared techniques) and the adverse effects on radio communications. Ultimately we propose to produce a well researched basis for managing radio communications in these naturally occurring ionizing events in the atmosphere.

Physics of remotely sensing the dynamic shoreline
M.L. Heron
  Video imaging is an economical and effective way to monitor coastal processes in very shallow water and has been successfully used to monitor breaker zones. There is a change in the red:blue balance in the images as we scan across the shoreline which is being used to record the dynamics of active beaches on long time scales of weeks, months and seasons. There is a rapid uptake of this technology because it is low-cost and is an effective way to record long-term effects of sand transport and erosion. This project will calibrate the red:blue balance in a close-up study on the beach.

Submarine Groundwater Discharge from Wonky Holes
P.V. Ridd (Physics, JCU), T. Stieglitz (Physics, JCU), Brunskill (AIMS)
  This project investigates submarine groundwater discharge (SGD) to the Great Barrier Reef (GBR) lagoon from point sources called "Wonky Holes". Wonky Holes are reputedly common yet scientifically unexplored in the GBR or elsewhere. Groundwater often contains high loads of nutrients and pollutants, and therefore SGD may constitute a significant pathway for nutrients etc. into the near-shore zone. This project will define the incidence and origin of Wonky Holes, and determine the magnitude, physical and chemical properties of their discharges. These studies will advance our understanding of land-sea interactions, assist management of the GBR, and improve regional hydrogeological models.

Acoustic Mapping of Seabed Habitats
Stieglitz (Physics, JCU), Heron (Physics, JCU), Wust (Earth Sciences, JCU), Coomans (Mathematics, JCU), Cappo (AIMS), Speare (AIMS)
  In the Great Barrier Reef Marine Park, much of the seabed and its biota remain little studied to date, mainly due to the large size of the park and lack of adequate techniques. In this project, rapid acoustic remote sensing techniques are used, and combined with physical/mathematical signal analysis and geological/biological ground-truthing, to (a) develop an effective survey strategy for seabed habitat studies and (b) to derive a catalogue of physical attributes of key habitats in the region. The outcomes of this project will provide a non-intrusive toolkit for effective assessment and monitoring of shallow marine habitats.

VHF Ocean Radar Evaluation of Sediment Dynamics in an Exposed Tidal Inlet
M.L. Heron
  The JCU VHF ocean radar is being applied to the study of sediment transport in a typical high energy coastal inlet as a part of a major international project in Portugal. The VHF radar will be used to map surface currents and wave heights on a small-scale grid at the estuary mouth and will provide an empirical model for sediment transport in terms of the primary parameters of waves and currents. The work will be carried out in the context of a multi-nation project in which a broad infrastructure of monitoring will be available from the group of collaborators. Our data will be deposited in the project database.

High resolution measurement of seabed erosion of cohesive sediments
P. Ridd
  Prediction of the movement of muddy sediment in Bays and Estuaries is an important practical problem as muddy sediments can be responsible for smothering of coral and sometimes contain high concentrations of contaminants such as heavy metals. The science of predicting the movement of muddy sediment is restricted because it is presently impossible to measure erosion or deposition rates at short timescales with any accuracy. Numerical models used for predicting movement of mud thus do not have sufficient input data to give accurate results. This project aims at producing a logging sensor that will be able to measure erosion or deposition with a resolution of 50 microns.

Axial Convergences in Mangrove Fringed Estuaries
P. Ridd
  Axial convergences are a form of cross river water movement formed by an interaction of the cross river velocity gradient and the along river salinity gradient. These convergences have recently been found to concentrate mangrove seeds in mid channel on flood tides and on the river banks on ebb tides. Because water in mid channel moves much faster than water near the banks, the result is that mangrove seeds are moved upstream. Further, as the seeds are mid channel when the swamps are being flooded it is impossible for the seeds to move into the swamps and grow. This is likely to affect the recruitment of mangrove species. All work so far has centred on one river, the Normanby River. This project aims to look at 10 estuaries in the Gulf of Carpentaria to determine if the secondary cells are a common feature of North Australian mangrove fringed estuaries.

Measurement of Fine Structure in Surface Currents by VHF Ocean Radar
M.L. Heron
  In this project we will evaluate the ability of the VHF Ocean Surface Radar to map shears in the surface water flow. The JCU VHF radar is the only instrument available which has the potential to map currents to a spatial scale of 100 m, and this is a validation exercise. Current meters will be used during the employment of the radar to take comparative transect and point measurements, and one of the participating collaborators is producing a numerical hydrodynamical model of the area. Our main collaborator, Telstra, is interested because it is committed to the R&D of the instrument. A second collaborator, representing the Australian Yachting Federation, has a need to understand details about small-scale currents in Sydney Harbour. The outcomes from the project include evaluation of the radar technology for this type of task, and the production of environmental data and forecasting skills.

Microwave Refractivity over Tropical Oceans
M.L. Heron, G.S. Woods
  Microwave propagation in the evaporation duct above the ocean is a stronger effect in warm tropical waters than in temperate zones. There have been several papers on observations of the duct and indeed it is used for enhanced communications. We propose to investigate the time and space scales for the variability of the duct and build a process-based explanation for its existence in terms of fluctuations in humidity and temperature in the few metres above the surface of the ocean. By matching the variability in the radio wave amplitude along the duct with the fluctuations in temperature and humidity we will produce a realistic model to use in further predictions of the performance of the duct. The project involves accurate measurements of temperature and humidity along a microwave link between Orpheus Island and the Lucinda Sugar Jetty.

Mangrove Crabs and Their Burrows
P. Ridd, T. Stieglitz
  Mangrove swamps play a key role in the ecology and nutrient budgets of the near shore zone, and provide a nursery area for the juvenile stages of many commercial seafood species. Mangrove crabs are a vital part of the ecology of the mangrove swamps influencing both nutrient cycling and forest structure. Flow of water through the crab burrows helps to reduce problems of lack of oxygen in the impermeable mangrove soils helping mangroves plants survive. This project will provide useful information on both the ecology of the crabs and also the hydrodynamics of the flushing of the soil due to the crab burrows.

Mesoscale Meteorology on a Tropical Coast
M.L. Heron
  The synoptic scale gradient wind and its coupling with the strongly diurnal sea-breeze dominate the meteorology of continental coastlines in the tropics. While these two phenomena are well understood separately, their interaction is complex. This project investigates the Coupled Gradient Wind and Sea-breeze regimes on the tropical coastline and develops a predictive model for short-term fore-casting and now-casting for the Port at Lucinda. The project is going ahead with the support of the Bureau of Meteorology, AIMS, and the Lucinda Bulk Sugar Terminal Management Board and the model we produce has the potential to become more widely used in the operation of coastal maritime facilities.

Evaluation of Wave Monitoring for Short Term Meteorological Prediction
M.L. Heron, R.L. Jaycock
  This project seeks to use the theoretical and observed connections between wind parameters and wave heights to improve short-term weather forecasting at a coastal site. Wave heights within the Great Barrier Reef Lagoon are generated locally by mesoscale winds operating over short fetches and for short durations. We propose to set up a remote sensing wave height monitor on the jetty at Lucinda to monitor waves and to evaluate the contribution that wave monitoring can make to mesoscale short-term weather forecasting in the area.

Flow through animal burrows in mangrove swamps and associated nutrient fluxes
P.V. Ridd, M.J. Ridd
  The highly impervious clay soil environment in mangrove swamps creates a challenge for mangrove trees to exist. Extremely slow flows of groundwater result in salt accumulation around mangrove roots and conditions of low oxygen concentrations. The labyrinthine burrow systems of some mangrove crabs provide an efficient pathway for the exchange of nutrients, salt and oxygen and can be viewed as “arteries” of the swamp soil. The crucial role of mangrove crabs and burrows to the mangrove ecosystem will be shown by studying burrow morphology and measuring fluxes of nutrients.

Measuring the flushing time of the Great Barrier Reef Lagoon

P.V. Ridd, Mal Heron.

The susceptibility of a water mass to pollution is greatly affected by the flushing time, i.e. the characteristic time that the water is removed from the system. In the case of the Great Barrier Reef lagoon, inputs of nutrients and other pollutants are thought by some scientists to have degraded the ecosystem. In order to understand this problem better, measurements of the flushing time of the lagoon are required. In this project, salinity is used as a passive tracer in order to determine the flushing time. An airborne radiometer is used to measure salinity transects in the lagoon and simple advection diffusions models are used to infer flushing times from the salinity data. So far this work is showing that the lagoon is rapidly flushed and unlikely to suffer from largescale, long term eutrophication.

Adaptive wavelets in factor analysis
D. Coomans, O. De Vel
  Spectral data sets play a crucial role in many areas of science and technology. Near-infrared spectroscopy, for example, is an important, efficient, non-destructive chemical analysis method with wide applications in quality monitoring in Australian industries such as sugar processing, mineral exploration and mineral processing. It is also becoming a promising tool in several applications of large-scale ecological monitoring. This project will investigate a novel technique based on wavelet basis functions for extracting useful features from, and the intelligent interpretation of, high-dimensional spectral data sets in conjunction with a factor analysis procedure.

Adaptive Wavelet Regression in Statistical Monitoring and Quality Control
D. Coomans
  We will develop regression methods based on adaptive wavelets for high dimensional spectral data and relevant to statistical monitoring and industrial quality control. Spectral data sets play an ever increasingly crucial role in many areas of science and technology. For instance, nondestructive spectrometry techniques are becoming important chemical analysis methods with wide applications in quality monitoring in Australian industries such as sugar processing, textile, agriculture, mineral exploration and processing. These techniques rely on efficient information extraction from the spectral data they generate. Adaptive wavelet regression may prove to be an information extraction method superior to existing regression methods.

Sports Biomechanics
Kevin Ness, Rebecca Kerr, Doug Rosemond
  In general, research in sports biomechanics has one of two aims, either technique enhancment or injury prevention. For a given sport a particular movement pattern may be analyised from either a kinematics or kinetic perspective.A kinematic analysis involves the quantification of the movement of body and body segments through space and time. On the other hand, a kinetic analysis seeks to quantify the forces generated when some movement pattern is observed. Current work includes: 1) kinematics analysis of the field hockey penalty corner push-in, and 2) kinetic/kinematic analysis of the technique enhancement and the analyisis involved can be readily extended to the investigation of other sporting movements.