H. Niemann

Max Planck Institute for Plasma Physics - Greifswald

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M. Jakubowski

Max Planck Institute for Plasma Physics - Greifswald

150

T. S. Pedersen

Max Planck Institute for Plasma Physics - Greifswald

G. A. Wurden

Los Alamos National Laboratory

S. Bozhenkov

Max Planck Institute for Plasma Physics - Greifswald

Yu Gao

Forschungszentrum Jülich

P. Drewelow

Max Planck Institute for Plasma Physics - Greifswald

A. Puig Sitjes

Max Planck Institute for Plasma Physics - Greifswald

F. Effenberg

Princeton Plasma Physics Laboratory

M. Krychowiak

Max Planck Institute for Plasma Physics - Greifswald

Y. Feng

Max Planck Institute for Plasma Physics - Greifswald

Cooperative Institutions

Max Planck Institute for Plasma Physics

505

Max Planck Society

457

Max Planck Institute for Plasma Physics - Greifswald

441

Princeton Plasma Physics Laboratory

148

Forschungszentrum Jülich

135

Culham Science Centre

123

National Institute for Fusion Science

119

CEA Cadarache

114

Oak Ridge National Laboratory

106

Australian National University

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Validating the ASCOT modelling of NBI fast ions in Wendelstein 7-X stellarator

Journal of Instrumentation (2019)

S. Äkäslompolo P. Drewelow Yu Gao Adnan Ali C. Biedermann

The first fast ion experiments in Wendelstein 7-X were performed in 2018. They are one of the first steps in demonstrating the optimised fast ion confinement of the stellarator. The fast ions were produced with a neutral beam injection (NBI) system and detected with infrared cameras (IR), a fast ion loss detector (FILD), fast ion charge exchange spectroscopy (FIDA), and post-mortem analysis of plasma facing components. The fast ion distribution function in the plasma and at the wall is being modelled with the ASCOT suite of codes. They calculate the ionisation of the injected neutrals and the consecutive slowing down process of the fast ions. The primary output of the code is the multidimensional fast ion distribution function within the plasma and the distribution of particle hit locations and velocities on the wall. Synthetic measurements based on ASCOT output are compared to experimental results to assess the validity of the modelling. This contribution presents an overview of the various fast ion measurements in 2018 and the current modelling status. The validation and data-analysis is on-going, but the wall load IR modelling already yield results that match with the experiments.

Wendelstein 7-X

Neutral Beam Injection

10.1088/1748-0221/14/10/c10012

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Citations (17)

Observed composition of the ionosphere of Venus: Implications for the ionization peak and the maintenance of the nightside ionosphere

Icarus (1982)

H. A. Taylor R. E. Hartle H. Niemann L. H. Brace R. E. Daniell

Atmosphere of Venus

10.1016/0019-1035(82)90084-7

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Citations (26)

Validating the ASCOT modelling of NBI fast ions in Wendelstein 7-X

S. Äkäslompolo Adnan Ali J. Baldzuhn C. Biedermann S. Bozhenkov

Wendelstein 7-X

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Edge Plasma Properties from the first Island Divertor Campaign at Wendelstein 7-X

M. Otte R. König M. Krychowiak M. Jakubowski Y. Feng

Wendelstein 7-X

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The Methane Cycle on Titan: Surface-Atmosphere Thermochemical Coupling (Invited)

AGU Fall Meeting Abstracts (2010)

S. K. Atreya J. I. Lunine H. Niemann

Atmospheric methane

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Results from Langmuir Probe arrays in the scrape off layer of the Wendelstein 7-X Advanced Stellarator

B. D. Blackwell M. Endler K. Hammond L. Rudischhauser R. König

Wendelstein 7-X

Langmuir Probe

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Scrape-off layer physics in the initial campaign of Wendelstein 7-X

M. Jakubowski R. König T. S. Pedersen C. Biedermann J. Baldzuhn

Wendelstein 7-X

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Radiative Power Exhaust in the Island Divertor and Access to Controlled Detachment with Impurity Seeding

F. Effenberg S. Brezinsek Y. Feng M. Jakubowski R. König

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Deep Atmosphere Ammonia Mixing Ratio at Jupiter from the Galileo Probe Mass Spectrometer

Bulletin of the American Astronomical Society (1999)

P. R. Mahaffy H. Niemann J. Demick

New laboratory studies employing the Engineering Unit (EU) of the Galileo Probe Mass Spectrometer (GPMS) have resulted in a substantial reduction in the previously reported upper limit on the ammonia mixing ratio derived from the GPMS experiment at Jupiter. This measurement is complicated by background ammonia contributions in the GPMS during direct atmospheric sampling produced from the preceding gas enrichment experiments. These backgrounds can be quantified with the data from the EU studies when they are carried out in a manner that duplicates the descent profile of pressure and enrichment cell loading. This background is due to the tendency of ammonia to interact strongly with the walls of the mass spectrometer and on release to contribute to the gas being directly directed into the ion source from the atmosphere through a capillary pressure reduction leak. It is evident from the GPMS and other observations that the mixing ratio of ammonia at Jupiter reaches the deep atmosphere value at substantially higher pressures than previously assumed. This is a likely explanation for the previously perceived discrepancy between ammonia values derived from ground based microwave observations and those obtained from attenuation of the Galileo Probe radio signal.

Mixing ratio

Atmosphere of Jupiter

Jupiter (rocket family)

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Citations (10)

On the response of exospheric temperature on Venus to solar wind conditions

Journal of Geophysical Research Atmospheres (1991)

Jayanta Kar R. Paul R. Kohli K. K. Mahajan W. T. Kasprzak

Exospheric temperatures (T ex ) inferred from in‐situ measurements of neutral densities by the Pioneer Venus Orbiter have been analyzed to examine any possible dependence on solar wind dynamic pressure (P sw ). We do not find any linear relationship between P sw and T ex . However, on one occasion when P sw was unusually high for a prolonged period, an unmistakable temperature enhancement was observed. Minor enhancements of T ex were also observed in a few other cases, with sustained but moderately high P sw .

Orbiter

Exosphere

Atmosphere of Venus

Solar maximum

Atmospheric temperature

10.1029/90ja02381

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Citations (1)