11 research outputs found
Solar parameters for modeling interplanetary background
The goal of the Fully Online Datacenter of Ultraviolet Emissions (FONDUE)
Working Team of the International Space Science Institute in Bern, Switzerland,
was to establish a common calibration of various UV and EUV heliospheric
observations, both spectroscopic and photometric. Realization of this goal
required an up-to-date model of spatial distribution of neutral interstellar
hydrogen in the heliosphere, and to that end, a credible model of the radiation
pressure and ionization processes was needed. This chapter describes the solar
factors shaping the distribution of neutral interstellar H in the heliosphere.
Presented are the solar Lyman-alpha flux and the solar Lyman-alpha resonant
radiation pressure force acting on neutral H atoms in the heliosphere, solar
EUV radiation and the photoionization of heliospheric hydrogen, and their
evolution in time and the still hypothetical variation with heliolatitude.
Further, solar wind and its evolution with solar activity is presented in the
context of the charge exchange ionization of heliospheric hydrogen, and in the
context of dynamic pressure variations. Also the electron ionization and its
variation with time, heliolatitude, and solar distance is presented. After a
review of all of those topics, we present an interim model of solar wind and
the other solar factors based on up-to-date in situ and remote sensing
observations of solar wind. Results of this effort will further be utilised to
improve on the model of solar wind evolution, which will be an invaluable asset
in all heliospheric measurements, including, among others, the observations of
Energetic Neutral Atoms by the Interstellar Boundary Explorer (IBEX).Comment: Chapter 2 in the planned "Cross-Calibration of Past and Present Far
UV Spectra of Solar System Objects and the Heliosphere", ISSI Scientific
Report No 12, ed. R.M. Bonnet, E. Quemerais, M. Snow, Springe
Solar Weather Event Modelling and Prediction
Key drivers of solar weather and mid-term solar weather are reviewed by considering
a selection of relevant physics- and statistics-based scientific models as well as aselection of related prediction models, in order to provide an updated operational scenario
for space weather applications. The characteristics and outcomes of the considered scientific
and prediction models indicate that they only partially cope with the complex nature of solar
activity for the lack of a detailed knowledge of the underlying physics. This is indicated by
the fact that, on one hand, scientific models based on chaos theory and non-linear dynamics
reproduce better the observed features, and, on the other hand, that prediction models
based on statistics and artificial neural networks perform better. To date, the solar weather
prediction success at most time and spatial scales is far from being satisfactory, but the forthcoming
ground- and space-based high-resolution observations can add fundamental tiles to
the modelling and predicting frameworks as well as the application of advanced mathematical
approaches in the analysis of diachronic solar observations, that are a must to provide
comprehensive and homogeneous data sets.peerReviewe