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The nuclear core of sun: theoretical perspectives and characterization of the scientific performances of the GOLF / SOHO experiment detector; La region nucleaire du soleil: perspectives theoriques et caracterisation des performances scientifiques du detecteur de l`experience GOLF / SOHO

Abstract

The subject of this thesis is the nuclear core of the sun. The first part is theoretical and concerns neutrino flux predictions. A precise description of the solar plasma is necessary to predict boron, beryllium and CNO cycle neutrinos. We treat here the nuclear reaction rates. They are mainly determined by the cross sections and the enhancement factors due to plasma particles, the co-called screening factors. We have discussed the various possible formalisms that could be used in stellar evolution and performed direct calculations of screened cross sections. We concluded that the screening prescriptions which have been used so far in stellar evolution should be replaced by the Mitler formalism. Next, we examine the cross section uncertainties and we show that it is possible to get a better agreement between theory and experiment. Discrepancies between the gallium experiments and the calculations suggest that we should go beyond the classical solar model. This has motivated our study on possible magnetic fields deeply buried in the solar core. We discuss here the influence of a magnetic pressure perturbation on solar evolution. In the experimental part of this work, we deal with the GOLF experiment, one of the three helio-seismological experiments on board  More>>
Authors:
Publication Date:
Jun 23, 1995
Product Type:
Thesis/Dissertation
Report Number:
FRCEA-TH-595
Reference Number:
SCA: 662430; 440103; PA: AIX-28:065555; EDB-98:022678; SN: 97001855829
Resource Relation:
Other Information: TH: These (D. es Sc.).; PBD: 23 Jun 1995
Subject:
66 PHYSICS; 44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; NUCLEAR CORES; SOLAR ACTIVITY; SUN; BERYLLIUM; BORON; CNO CYCLE; COSMIC PHOTONS; COUNTING RATES; CROSS SECTIONS; DATA ACQUISITION SYSTEMS; DEAD TIME; DOPPLER EFFECT; ELECTRONIC EQUIPMENT; GAIN; HYDROGEN BURNING; HZ RANGE; MAGNETIC FIELDS; NOISE; NUCLEAR REACTIONS; OSCILLATION MODES; PERFORMANCE TESTING; PHOTOCATHODES; PHOTOMULTIPLIERS; SEISMOLOGY; SIMULATION; SOLAR NEUTRINOS; SOLAR NEUTRONS; SPACE; SPACE VEHICLES; THERMONUCLEAR REACTIONS; VELOCITY; WAVELENGTHS
OSTI ID:
568476
Research Organizations:
Institut National des Sciences et Techniques Nucleaires (INSTN), Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Paris-11 Univ., 91 - Orsay (France)
Country of Origin:
France
Language:
French;English
Other Identifying Numbers:
Other: ON: DE98601212; TRN: FR9703926065555
Availability:
INIS; OSTI as DE98601212
Submitting Site:
FRN
Size:
297 p.
Announcement Date:

Citation Formats

Dzitko, H. The nuclear core of sun: theoretical perspectives and characterization of the scientific performances of the GOLF / SOHO experiment detector; La region nucleaire du soleil: perspectives theoriques et caracterisation des performances scientifiques du detecteur de l`experience GOLF / SOHO. France: N. p., 1995. Web.
Dzitko, H. The nuclear core of sun: theoretical perspectives and characterization of the scientific performances of the GOLF / SOHO experiment detector; La region nucleaire du soleil: perspectives theoriques et caracterisation des performances scientifiques du detecteur de l`experience GOLF / SOHO. France.
Dzitko, H. 1995. "The nuclear core of sun: theoretical perspectives and characterization of the scientific performances of the GOLF / SOHO experiment detector; La region nucleaire du soleil: perspectives theoriques et caracterisation des performances scientifiques du detecteur de l`experience GOLF / SOHO." France.
@misc{etde_568476,
title = {The nuclear core of sun: theoretical perspectives and characterization of the scientific performances of the GOLF / SOHO experiment detector; La region nucleaire du soleil: perspectives theoriques et caracterisation des performances scientifiques du detecteur de l`experience GOLF / SOHO}
author = {Dzitko, H}
abstractNote = {The subject of this thesis is the nuclear core of the sun. The first part is theoretical and concerns neutrino flux predictions. A precise description of the solar plasma is necessary to predict boron, beryllium and CNO cycle neutrinos. We treat here the nuclear reaction rates. They are mainly determined by the cross sections and the enhancement factors due to plasma particles, the co-called screening factors. We have discussed the various possible formalisms that could be used in stellar evolution and performed direct calculations of screened cross sections. We concluded that the screening prescriptions which have been used so far in stellar evolution should be replaced by the Mitler formalism. Next, we examine the cross section uncertainties and we show that it is possible to get a better agreement between theory and experiment. Discrepancies between the gallium experiments and the calculations suggest that we should go beyond the classical solar model. This has motivated our study on possible magnetic fields deeply buried in the solar core. We discuss here the influence of a magnetic pressure perturbation on solar evolution. In the experimental part of this work, we deal with the GOLF experiment, one of the three helio-seismological experiments on board the space probe SOHO. The purpose of this instrument is the study of the global oscillation modes in the frequency range 10{sup -7} to 6 10{sup -3} Hz with a sensitivity for frequencies higher than 2 10{sup -4} Hz of about 1 mm/s over 20 days of continuous integration at counting rates of 12 10{sup 6} cs/s. One part of this work was devoted to the precise characterization of the photomultipliers and their associated electronics in order to select them according to their intrinsic performances. This step was followed by long duration tests of three weeks simulating as well as possible the flight conditions. We show that the detection chain effectively meets the stability requirements of around 10{sup -7} by velocity measurement. (Abstract Truncated)}
place = {France}
year = {1995}
month = {Jun}
}