scholarly journals Solar Particles Seen by Ulysses Near 33°S

1996 ◽  
Vol 154 ◽  
pp. 199-202
Author(s):  
S.J. Tappin ◽  
G.M. Simnett
Keyword(s):  
Solar Wind ◽  
Solar Source ◽  
Particle Event ◽  
Solar Particles

AbstractObservations of a particle event (electrons >40 keV; ions >50 keV) at heliographic mid-latitudes are presented. The particles are shown to originate from an apparently insignificant solar source and to be stored prior to release into the solar wind.

scholarly journals FLIP-MHD-based model sensitivity analysis

2014 ◽  
Vol 21 (2) ◽  
pp. 539-553 ◽  
Author(s):  
C. Skandrani ◽  
M. E. Innocenti ◽  
L. Bettarini ◽  
F. Crespon ◽  
J. Lamouroux ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Wind Speed ◽  
Sensitivity Study ◽  
Field Configuration ◽  
Source Surface ◽  
Solar Source ◽  
Surface Magnetic Field ◽  
Model State ◽  
The Impact

Abstract. The state of the art in the forecast of the background solar wind speed and of the interplanetary magnetic field at Earth is based on the use as boundary conditions for heliospheric models of the input data provided by solar observations. Magnetogram synoptic maps are used to obtain information on the magnetic field configuration at the solar source surface. Magnetic field inputs at the solar source surface thus constitute one of the main external sources of errors in solar wind models. The assimilation of data into forecasting models used in the terrestrial domain showed the ability to control model state errors. A sensitivity study performed through the analysis of the ensemble variances and the representers technique is used here to assess how process and model state errors propagate in a nonlinear two-dimensional MagnetoHydro Dynamic (MHD) system. The aim is to understand the impact of the source surface input parameters on the evolution of MHD heliospheric models and the potentialities of data assimilation techniques in solar wind forecasting. The representer technique in fact allows one to understand how far from the observation point the improvement granted from the assimilation of a measure propagates.

scholarly journals On the Dependency between the Peak Velocity of High-speed Solar Wind Streams near Earth and the Area of Their Solar Source Coronal Holes

2020 ◽  
Vol 897 (1) ◽  
pp. L17
Author(s):  
Stefan J. Hofmeister ◽  
Astrid M. Veronig ◽  
Stefaan Poedts ◽  
Evangelia Samara ◽  
Jasmina Magdalenic
Keyword(s):  
Solar Wind ◽  
High Speed ◽  
Peak Velocity ◽  
Coronal Holes ◽  
Solar Source ◽  
Speed Solar Wind ◽  
High Speed Solar Wind

scholarly journals Modeling 1 AU solar wind observations to estimate azimuthal magnetic fields at the solar source surface

2011 ◽  
Vol 38 (24) ◽  
pp. n/a-n/a ◽  
Author(s):  
Hagen Schulte in den Bäumen ◽  
Iver H. Cairns ◽  
P. A. Robinson
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Source Surface ◽  
Solar Source

Interplanetary ions during an energetic storm particle event: The distribution function from solar wind thermal energies to 1.6 MeV

1981 ◽  
Vol 86 (A2) ◽  
pp. 547 ◽  
Author(s):  
J. T. Gosling ◽  
J. R. Asbridge ◽  
S. J. Bame ◽  
W. C. Feldman ◽  
R. D. Zwickl ◽  
...  
Keyword(s):  
Solar Wind ◽  
Distribution Function ◽  
Particle Event

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Quantitative surface damage studies by H.R.E.M.

1989 ◽  
Vol 47 ◽  
pp. 632-633
Author(s):  
S. R. Singh ◽  
H. J. Fan ◽  
L. D. Marks
Keyword(s):  
Solar Wind ◽  
Quantitative Analysis ◽  
Surface Science ◽  
Surface Damage ◽  
Space Environment ◽  
Oxygen Desorption ◽  
The Past ◽  
Diffusion Controlled ◽  
Original Observation ◽  
Substantial Interest

Since the original observation that the surfaces of materials undergo radiation damage in the electron microscope similar to that observed by more conventional surface science techniques there has been substantial interest in understanding these phenomena in more detail; for a review see. For instance, surface damage in a microscope mimics damage in the space environment due to the solar wind and electron beam lithographic operations.However, purely qualitative experiments that have been done in the past are inadequate. In addition, many experiments performed in conventional microscopes may be inaccurate. What is needed is careful quantitative analysis including comparisons of the behavior in UHV versus that in a conventional microscope. In this paper we will present results of quantitative analysis which clearly demonstrate that the phenomena of importance are diffusion controlled; more detailed presentations of the data have been published elsewhere.As an illustration of the results, Figure 1 shows a plot of the shrinkage of a single, roughly spherical particle of WO3 versus time (dose) driven by oxygen desorption from the surface.

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