A5033029609- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- GNSS positioning and interference
- Advanced Radiotherapy Techniques
- Radiation Therapy and Dosimetry
- Geophysics and Gravity Measurements
- Magnetic confinement fusion research
- Atmospheric Ozone and Climate
- Seismic Waves and Analysis
- Medical Imaging Techniques and Applications
- Advanced X-ray and CT Imaging
- Radiation Detection and Scintillator Technologies
- Astro and Planetary Science
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- earthquake and tectonic studies
- Radiation Dose and Imaging
- Radio Astronomy Observations and Technology
- Space exploration and regulation
- Meteorological Phenomena and Simulations
- Satellite Communication Systems
- Spacecraft Design and Technology
- Geophysics and Sensor Technology
University of Newcastle Australia
2010-2024
John Wiley & Sons (United States)
2015
Charles River Laboratories (Netherlands)
2015
Calvary Mater Newcastle Hospital
2011
Commonwealth Scientific and Industrial Research Organisation
2011
University of Oxford
2001
Avondale University
1998
La Trobe University
1983-1986
The spectral difference in ULF wave amplitude between closely spaced meridional ground stations may be used to measure the eigenfrequency of magnetospheric field lines [Baransky et al., 1985]. A more reliable technique based on crossphase spectrum has been identify eigenfrequencies and study temporal evolution local line resonances. Pc3 (22–100 mHz) pulsations recorded with two pairs low latitude have specifically examined. Resonances harmonics whose frequencies are excellent agreement model...
The Antarctic‐Arctic Radiation‐belt (Dynamic) Deposition‐VLF Atmospheric Research Konsortium (AARDDVARK) provides a network of continuous long‐range observations the lower ionosphere in polar regions. Our ultimate aim is to develop sensors detect changes ionization levels from ∼30–90 km altitude, globally, continuously, and with high time resolution, goal increasing understanding energy coupling between Earth's atmosphere, Sun, space. This science area impacts our knowledge space weather...
Abstract Ionization of the Earth's atmosphere by sunlight forms a complex, multilayered plasma environment within magnetosphere, innermost layers being ionosphere and plasmasphere. The plasmasphere is believed to be embedded with cylindrical density structures (ducts) aligned along magnetic field, but direct evidence for these remains scarce. Here we report first wide‐angle observation an extensive array field‐aligned ducts bridging upper inner plasmasphere, using novel ground‐based imaging...
It is well known that the resonant frequency of geomagnetic field lines determined by magnetic and plasma density. We used cross‐phase related methods to determine line resonance across 2.4≤<L≤4.5 in Northern Hemisphere at 78°–106° longitude centered on L=2.8 Southern 226° longitude, for several days October November 1990. The temporal spatial variation mass density was thus compared with VLF whistler measurements electron densities similar times locations. loading estimated found be low,...
Abstract The response of the D region low‐latitude ionosphere has been examined for extreme space weather event 14–16 December 2006 associated with a X1.5 solar flare and an intense geomagnetic storm ( Dst = −146 nT) using VLF signals from Northwest Cape, Australia (NWC) (19.8 kHz) Lualualei, Hawaii (callsign NPM) (21.4 transmitters monitored at Suva (Geographic Coordinates, 18.10°S, 178.40°E), Fiji. Modeling amplitude phase enhancements NWC (3.6 dB, 223°) NPM (5 153°) Long‐Wave Propagation...
Several recent publications have reported high‐latitude radar observations of field line resonances (FLRs) displaying discrete and very stable frequencies in the Pc5 range. It is believed that these quantized frequency FLRs may be associated with cavity/waveguide harmonics outer magnetosphere but prevalence stability remains controversial. We examine statistics 137 pulsation events identified from 3 months magnetometer data International Monitor for Auroral Geomagnetic Effects (IMAGE) show...
Geomagnetic field line resonances may be identified in ground magnetometer data by comparing the difference amplitude and phase of signals recorded at two closely spaced sites or examining latitudinal variation polarization properties across a more extended array. These methods give comparable results for values resonant frequency width low latitudes ( L < 3). We have also found an upper limit damping factor, γ∼0.07 =1.8, applying damped simple harmonic oscillator model. The resonance...
Field line resonances (FLRs) are an important mechanism for the generation of Pc3–4 (∼7–100 mHz) geomagnetic pulsations. There is considerable observational evidence existence FLRs at middle latitudes, both in satellite and ground data. However, low‐latitude regions less accessible such studies, consequently many aspects not well understood. A temporary 12‐station magnetometer array spanning eastern Australia from L = 1.3–2.0 was used to investigate variation power with latitude, nature...
The plasmasphere seems the most likely magnetospheric region in which compressional hydromagnetic waves may be trapped to form cavity modes. It has been suggested that substorm‐associated Pi2 magnetic pulsations have a mode character at low latitudes. Recent detailed observations of night‐side events latitudes also or waveguide character. We apply well‐tried numerical wave coupling model latitudes, and compare output with these observations. find qualitative amplitude phase characteristics...
This paper presents a coordinated ground‐based magnetometer and IMAGE satellite study of plasma mass density plasmapause location on L shells between 2.39 6.54 throughout an extended interval moderate geomagnetic activity from 5 to 17 May 2001. Storm‐time plasmaspheric depletion is monitored using three different data sets, our results show the importance local time history effects depletion, including determining that shorter intervals enhanced convection do not necessarily cause all...
The relation between Pi 1–2 pulsations on the ground and substorm‐associated magnetic field variations in space has been studied using data obtained at low‐latitude conjugate stations ( L = 1.3–2.1) near‐Earth magnetotail by AMPTE CCE spacecraft. ground‐based were acquired a campaign period from July 20 to September 16, of 1986, during which apogee (8.8 R E ) was located 2330 0230 hours local time. Of 16 clear dipolarizations observed CCE, all had corresponding 2 pulsation ground, with time...
To clinically implement MRI simulation or MRI-alone treatment planning requires comprehensive end-to-end testing to ensure an accurate process. The purpose of this study was design and build a geometric phantom simulating human male pelvis that is suitable for both CT scanning use it test dosimetric aspects including digitally reconstructed radiograph (DRR) generation.A liquid filled pelvic shaped with simulated organs scanned in 3T simulator dedicated radiotherapy couch-top, laser bridge...
Geosynchronous Los Alamos National Laboratory (LANL‐97A) satellite particle data, riometer and radio wave data recorded at high geomagnetic latitudes in the region south of Australia New Zealand are used to perform first complete modeling study effect substorm electron precipitation fluxes on low‐frequency propagation conditions associated with dispersionless injection events. We find that precipitated energy spectrum is consistent an e ‐folding 50 keV for energies <400 but also contains...
It is generally accepted that electromagnetic ion cyclotron (EMIC) waves are generated around the equatorial regions and propagate toward high latitude ionospheres in both hemispheres. Here we describe a prolonged EMIC wave event Pc2 (0.1–0.2 Hz) frequency band above He + detected by four Cluster satellites as they traversed sunward from L ∼ 13 outer magnetosphere to magnetopause, over 13°–20° magnetic north of equator across cusp region near local noon. Wave packet energy propagated...
Using Pc5 pulsation events observed with the IMAGE magnetometer array, we demonstrate that mHz frequency field line resonances (FLRs) represent local enhancements in background Alfvén continuum of eigenfrequencies. By comparing resonance profiles for a typical event profile determined using cross‐phase techniques, show frequencies as low 1–2 can couple to FLRs on high latitude closed lines. We also suggest transition open lines days higher geomagnetic activity may lead breakdown...
The power spectra of magnetometer data recorded at low latitudes show a remarkable similarity over the latitudinal range, 1.3< L <2.0. Power from sites along east coast Australia similar fine structure where adjacent maxima are spaced between 3 and 5 mHz apart. H component also superposed feature spectrum that varies with latitude according to expected for field line resonance. In order explain these data, propagation fast mode, ULF wave energy through one‐dimensional model...
Measurements of ionospheric E × B drifts obtained with HF radars from the SuperDARN (Super Dual Auroral Radar) Network sometimes show signatures ULF (few mHz) waves. We present a new data display technique that facilitates detection waves in both ground and sea scatter returns. Statistical study high time resolution TIGER radar Tasmania, Australia, revealed wave occur on an everyday basis accounting for about 60% events. About half these events exhibit coherence across large spatial...
This paper discusses the use of ground magnetometer data to derive plasma mass density profiles dayside plasmapause region with spatial and temporal resolution in range 0.15–0.4 R E 20–60 min. is achieved using cross‐phase techniques identify field line resonance signatures that are not apparent power spectra. Under quiet conditions, do show a distinct closely resemble electron for similar conditions. more active conditions can be clearly identified, its width resolved about 20% cases....
In order to identify the generation mechanisms of low‐latitude Pc3–4 geomagnetic pulsations, data were obtained from a meridional chain induction magnetometers spanning L values 1.4 2.7 (−30° −52° latitude). The spatial structure signal parameters was examined by means spectral, polarization and interstation phase analysis. This paper describes three typical individual events whose characteristics indicate existence field line resonances at low latitudes within plasmasphere. shows local...