Research Interests & Publications

Java and the Web

I have been writing (intermittently) a Java package to allow the dynamic loading across the web and plotting of two dimensional data. A number of examples demonstrating the Graphics Classes are available for viewing and downloading.

Smoothed Particle Hydrodynamics (SPH)

This is a numerical method that uses moving points (or more commonly particles as the points carry their mass with them) to represent fluid flow. Physical quantities (and derivatives) are interpolated from the moving points.

The methods main advantage over more familar methods is its ease of coding and its flexibility.

(A general reference, for those interested, is [1]).

Origins of Life

My interest in this topic is mainly concerned with (but not restricted to) the sources of prebiotic organic molecules important for the origins of life. The sources of organic molecules on the early Earth can be loosely divided into three categories (see the review article [2])

• delivery by extraterrestrial objects
• endogenous synthesis driven by impact shocks
• endogenous synthesis by other energy sources

Using SPH (in collaboration with others) we have modelled hypervelocity impacts of comets and carbonaceous chondrites on the early earth (see [3]) and found that organic molecules can survive hypervelocity impacts the impact velocity must be below 10km/sec into water for substantial amounts to survive impact.

Pulsar Binaries

A number of binary millisecond pulsars have been found in the process of evaporating their companion stars (eg. PSR 1957+20 and PSR 1744-24A). Using SPH it has been possible to model the hydrodynamic wind outflow from the irradiated companion star (see [4], [5], [6]).

Using the same scenario it has also been possible to suggest a mechanism for the formation of the planets around pulsar PSR1257+12 (see [7]).

Hypervelocity Impacts

Using SPH to model laboratory hypervelocity experiments. The current simulations are of scram-jets impacting into a sand bunker using the LLNL SHARP gun.

Publications

Leigh Brookshaw