Engineering topics

Hoefner, H.

Publications and source records attributed to Hoefner, H..

4 records

NASA NTRS1985

The AMPTE IRM Science Data Center

The creation of artificial ion clouds is a major aspect of the AMPTE program. The IRM Science Data center supports real-time decision for a release with real-time scientific data processing and display including model calculations of ion trajectories. Additionally, survey plots and summary data records are generated in near real time thus allowing to start the data analysis as early as possible. For detailed analyses, interactive programs were developed so that physical parameters of all IRM experiments can be combined to produce common spectra or line plots.

Bauer, O. H.↗

NASA NTRS1982

Ionic charge state distribution of helium, carbon, oxygen, and iron in an energetic storm particle enhancement

An analysis is presented of the ionic charge state distribution of He, C, O and Fe in the energetic storm particle event of September 28-29, 1978. Data were obtained with the ULEZEQ electrostatic analyzer-proportional counter on board the ISEE 3 spacecraft. The He(+)/He(++) ratio between 0.4 and 1 MeV/n is shown to be significantly lower during the energetic storm particle event than during the preceding period of solar flare particle enhancement, with a temporal evolution similar to that of the Fe/He ratio as reported by Klecker et al. (1981). Increases in the mean charge state for oxygen by about 3% and for iron by about 16% are also noted. The temporal variations in charge states are accounted for in terms of first-order Fermi acceleration of the pre-existing solar flare particles by a propagating interplanetary shock wave.

Hovestadt, D.↗

NASA NTRS1981

Singly charged energetic helium emitted in solar flares

First direct charge state measurements of 0.41-1.05 MeV per nucleon helium accelerated at the sun reveal surprisingly large abundances of singly ionized helium, with typical He(+)/He(++) ratios between 0.04 and 0.21. This unexpected overabundance of He(+) was observed in each of the three large solar-flare particle events which occurred between 1978 August and 1979 October. The data were obtained with the Max-Planck-Institut/University of Maryland Experiment on board the ISEE-3 spacecraft. The observations suggest either strong coronal temperature inhomogeneities including cool regions of approximately 100,000 K or injection of 'cold' chromospheric/photospheric material into the flare acceleration region.

Hovestadt, D.↗

NASA NTRS1981

Direct observation of charge state abundances of energetic He, C, O, and Fe emitted in solar flares

The ionic charge states of helium, carbon, oxygen, and iron have been determined for three solar particle enhancements by an electrostatic deflection analyzer, which is combined with a thin window proportional counter dE/dX vs. E system. The observations are obtained during the periods September 23 to 29, 1978, June 6 to 8, 1979, and September 15 to 26, 1979, with an instrument onboard the ISEE-3 spacecraft. The mean ionic charge states for He, C, and oxygen exhibit a high degree of ionization with values of Q equals 2, 6, and 7.2, respectively. The charge state of iron is near 13 charge units. Variations from flare to flare and within the September 23, 1978 flare are small. The most surprising feature of the charge state measurement is the observation of a small (about 10%) but finite contribution of singly ionized helium.

Hovestadt, D.↗