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Igenbergs, E. B.

Publications and source records attributed to Igenbergs, E. B..

Composition of comet Halley dust particles from Giotto observations

Mass spectra of cometary dust particles measured by the PIA dust particle analyzer aboard the Giotto spacecraft show some unexpected and striking features. First, small particles below 10 to the -14th g are much more abundant than anticipated by models. Second, most of the particles are rich in light elements such as H, C, N, and O, suggesting the validity of models that describe the cometary dust as including organic material. Third, the light elements specifically seem to have a low ratio of mass to volume. Three examples of original mass spectra showing typical compositions are given; these have been measured, and are compared with a computer-simulated mass spectrum.

Kissel, J.

Plasma flow and fast particles in a hypervelocity accelerator - A color presentation

A new concept for particle acceleration for micrometeoroid simulation was developed at NASA Marshall Space Flight Center, using a high-density self-luminescent fast plasma flow to accelerate glass beads (with a diameter up to 1.0 mm) to velocities between 15-20 km/sec. After a short introduction to the operation of the hypervelocity range, the eight-converter-camera unit used for the photographs of the plasma flow and the accelerated particles is described. These photographs are obtained with an eight-segment reflecting pyramidal beam splitter. Wratten filters were mounted between the beam splitter and the converter tubes of the cameras. The photographs, which were recorded on black and white film, were used to make the matrices for the dye-color process, which produced the prints shown.

Igenbergs, E. B.

New two-stage accelerator for hypervelocity impact simulation

The present knowledge of the micrometeoroid environment and the simulation requirements for laboratory devices show that the simulated mass-velocity range must be extended to higher values in both mass and velocity. This is accomplished with the new two-stage accelerator, which consists of a light gas gun as the first stage and a coaxial accelerator with a compressor coil as the second stage. The operation of the new device is described together with a theoretical investigation of the timing of the first and the second stage, which leads to an appropriate adjustment of the two stages. The theoretical and experimental results agree well and show that 600-micron diameter glass beads have been accelerated to velocities near 20 km/sec.

Igenbergs, E. B.

Self-energized plasma compressor

The self-energized plasma compressor is described which compresses plasma discharged from a coaxial plasma generator. The device includes a helically shaped coil which is coaxially aligned with the center axis of the coaxial plasma generator. The plasma generator creates a current through the helical coil which, in turn, generates a time varying magnetic field that creates a force which acts radially upon the plasma. The coaxial plasma generator and helical coil move the plasma under high pressure and temperature to the narrow end of the coil. Positioned adjacent to the narrow end of the coil are beads which are engaged by the plasma to be accelerated to hypervelocities for simulating meteoroids.

Shriver, E. L.

Magnetogasdynamic compression of a coaxial plasma accelerator flow for micrometeoroid simulation

A new configuration of a coaxial plasma accelerator with self-energized magnetic compressor coil attached is described. It is shown that the circuit may be treated theoretically by analyzing an equivalent circuit mesh. The results obtained from the theoretical analysis compare favorably with the results measured experimentally. Using this accelerator configuration, glass beads of 125 micron diameter were accelerated to velocities as high as 11 kilometers per second, while 700 micron diameter glass beads were accelerated to velocities as high as 5 kilometers per second. The velocities are within the hypervelocity regime of meteoroids.

Igenbergs, E. B.

Magnetogasdynamic compression of a coaxial plasma accelerator flow for micrometeoroid simulation.

A new configuration of a coaxial plasma accelerator with self-energized magnetic compressor coil attached is described. It is shown that the circuit may be treated theoretically by analyzing an equivalent circuit mesh. The results obtained from the theoretical analysis are shown to compare favorably with the results measured experimentally. Using this accelerator configuration, glass beads of 125-micron diameter were accelerated to velocities as high as 11 km/sec, while 700-micron-diam glass beads were accelerated to velocities as high as 5 km/sec. The velocities are within the hypervelocity regime of meteroids.

Igenbergs, E. B.