Engineering topics

Rinnert, K.

Publications and source records attributed to Rinnert, K..

7 records

NASA NTRS1992

Energetic Particles Investigation (EPI)

The EPI instrument operates during the pre-entry phase of the Galileo Probe. The main objective is the study of the energetic particle population in the inner Jovian magnetosphere and in the upper atmosphere. This will be achieved through omnidirectional measurements of electrons, protons, alpha-particles and heavy ions (Z greater than 2) and recording intensity profiles with a spatial resolution of about 0.02 Jupiter radii. Sectored data will also be obtained for electrons, protons, and alpha-particles to determine directional anisotropies and particle pitch angle distributions. The detector assembly is a two-element telescope using totally depleted circular silicon surface-barrier detectors surrounded by cylindrical tungsten shielding. The lower energy threshold of the particle species investigated during the Probe's pre-entry phase is determined by the material thickness of the Probe's rear heat shield which is required for heat protection of the scientific payload during entry into the Jovian atmosphere. The EPI instrument is combined with the Lightning and Radio Emission Detector and both instruments share one interface of the Probe's power, command, and data unit.

Fischer, H. M.↗

NASA NTRS1992

The Lightning and Radio Emission Detector (LRD) instrument

The Lightning and Radio Emission Detector (LRD) instrument will be carried by the Galileo Probe into Jupiter's atmosphere. The LRD will verify the existence of lightning in the atmosphere and will determine the details of many of its basic characteristics. The instrument, operated in its magnetospheric mode at distances of about 5, 4, 3, and 2 planetary radii from Jupiter's center, will also measure the RF noise spectrum in Jupiter's magnetosphere. The LRD instrument is composed of a ferrite-core radio frequency antenna and two photodiodes mounted behind individual fisheye lenses. The output of the RF antenna is analyzed both separately and in coincidence with the optical signals from the photodiodes. The RF antenna provides data both in the frequency domain (with three narrow-band channels, primarily for deducing the physical properties of distant lightning) and in the time domain with a priority scheme (primarily for determining from individual RF waveforms the physical properties of closeby-lightning).

Lanzerotti, L. J.↗

NASA NTRS1989

Power spectra at radio frequency of lightning return stroke waveforms

The power spectra of the wideband (10 Hz to 100 kHz) magnetic field signals in a number of lightning return strokes (primarily first return strokes) measured during a lightning storm which occurred in Lindau, West Germany in August, 1984 have been calculated. The RF magnetic field data were obtained with the engineering unit of the Galileo Jupiter Probe lightning experiment. The spectra of the magnetic field data definitely show fine structure, with two or three distinct peaks appearing in the spectra of many of the waveforms. An enhancement of power at frequencies of about 60-70 kHz is often seen in the spectra of the waveform time segments preceding and following the rise-to-peak amplitude of the return stroke.

Lanzerotti, L. J.↗

NASA NTRS1988

Fine structure in RF spectra of lightning return stroke wave forms

The power spectra of the wide-band (10 Hz to 100 kHz) magnetic-field signals for a number of lightning return strokes measured during a thunderstorm which occurred in Lindau in August, 1984 have been calculated. The RF magnetic field data are obtained with the engineering unit of the Galileo Jupiter Probe lightning experiment. Each return stroke data stream is passed through an adaptive filter designed to whiten its spectrum. The spectra of the magnetic field data definitely show fine structure, with two or three distinct peaks in the spectra of many of the waveforms. A peak at f of about 60-70 kHz is often seen in the power spectra of the waveform time segments preceding and following the rise-to-peak amplitude of the return stroke.

Lanzerotti, L. J.↗

NASA NTRS1988

Lightning in Jupiter's atmosphere

This paper introduces some current ideas on the dynamical structure of Jupiter's atmosphere that are likely to be important for the generation of lightning and reviews briefly the present understanding of Jovian lightning. The Galileo probe into Jupiter's atmosphere is now scheduled for a space shuttle launch in October 1989, with the probe entry into Jupiter's atmosphere to occur in December 1995. The atmospheric probe carries a radio frequency (RF) and optical lightning detection instrument to investigate the characteristics of Jovian lightning,.

Lanzerotti, L. J.↗

NASA NTRS1985

Measurements of the RF characteristics of earth lightning with the Galileo probe lightning experiment

The results of some measurements of earth lightning made with the functional unit of the Galileo probe RF lightning experiment are presented. The frequency range used is about 100 Hz to 100 kHz. The measurements were carried out in conjunction with simultaneous studies of lightning sources made by the University of Florida lightning research group. It is found that the typical RF pulse duration times are less than 30 microsec, independent of lightning source distance (less than 250 km). It is also found that the time between successive pulses is either quite short (less than 64 microsec), corresponding to the time between intracloud pulses and to the time between bipolar pulses, or occur around 100 ms, corresponding to the time between return strokes in ground discharges. The RF spectra are found to become less steep (relatively more power at the higher frequencies) during an interval of intense, nearby (less than 150 km) storms.

Rinnert, K.↗

NASA NTRS1979

Electromagnetic noise and radio wave propagation below 100 kHz in the Jovian atmosphere. I - The equatorial region

The Galileo satellite program includes the delivery of an entry probe to the Jovian equatorial atmosphere in mid-1985. Optical and RF sensors for a lightning detection system are included as a part of the probe experimental payload. In this paper, calculations of the RF wave propagation and reflection characteristics of the equatorial Jovian atmosphere and ionosphere for frequencies less than 100 kHz are presented. It is shown that wave propagation is limited to line-of-sight and one-hop from the ionosphere. Results are also presented of a statistical treatment of the RF wave power densities for the case of a finite number of events and for the case of a uniformly distributed source. The results can be applied to specific RF experiment configurations concerned with establishing the statistical characteristics of Jovian lightning.

Rinnert, K.↗