Knowledge of the distribution of interplanetary and circumsolar dust particles and their physical and optical characteristics provides valuable information about many issues dealing with the origin and formation of the solar system. Interplanetary dust particles (IDP's) are considered to have their origin in cometary, astroidal, and meteoritic sources, along with possible contributions from planets and the pre-solar molecular cloud. Dust particles in the interplanetary medium are produced by a variety of sources and have a diverse size range. Particles ranging from 5 to 100 mm contribute to most to the zodiacal light, with a typical particle size of 30 mm. The major constituents of the spherical or irregularly shaped circumsolar and IDP's are believed to be silicates and carbonaceous materials, as indicated by analyses of stratospheric dust particles of interplanetary origin.
An experimental technique being developed in the laboratory at Marshall Spaced Flight Center for measurements of scattering and extinction cross sections of some commonly known interplanetary and circumsolar dust particles will be presented. This technique is based on irradiating a single charged dust particle suspended by electrodynamic balance in a cavity and measuring the scattered radiation as a function of angle. Comparison with Mie theory calculations leads to simultaneous determination of the particle radius, the complex refractive index, and the scattering and extinction cross sections. An application of this technique will also be discussed for investigation of rotational bursting phenomena whereby large size cosmic and interplanetary particles are believed to fragment into smaller dust particles.