摘要:

The study of solar neutrinos may provide important insights into the physics of the central region of the Sun. Four solar neutrino experiments have confirmed the solar neutrino problem but do not clearly indicate whether solar physics, nuclear physics, or neutrino physics have to be improved to solve it. Nonlinear relations among the different neutrino fluxes are imposed by two coupled systems of differential equations governing the internal structure and time evolution of the Sun. We assume that the results of the four neutrino experiments are correct and are concerned not with the discrepancy between the average rate and the predicted rate, but with a possible time dependence of the argon production rate as revealed in the Homestake experiment over a time period of 20 years. Based on the subtlety of the solar neutrino problem we review here qualitatively the physical laws employed for understanding the internal solar structure and conjecture that the interlink between specific nuclear reactions of the PPIII‐branch of the proton‐proton chain may allow the high‐energy solar neutrino flux to vary over time. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47009

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A short overview of the direct reaction mechanism and the models used for the analysis of such processes is given. Nuclear reactions proceeding through the direct mechanism and involved in solar hydrogen burning are discussed. The significance of these nuclear reactions with respect to the solar neutrino problem is investigated. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47010

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

X‐ray spectrum of a typical impulsive solar flare from a recent measurement, was used to estimate the electron injection flux, assuming a thick‐target model. ‘Knock‐on process’ or Coulomb scattering by high energy protons was shown to be a possible dominant physical mechanism that accounts for the production of mildly relativistic electrons in the flare. The estimated electron injection rate was found to be in reasonable agreement with the observational results. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47011

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A morphological description of the solar photosphere, chromosphere and the corona is presented from a complete sequence of visual and spectroscopic observations made in Honduras (Amapala), during the total solar eclipse of 11 July 1991 and from the analysis of some emission and absorption lines at all the eclipse phases. Also, a comparison of detected total flux of muons incident over Tegucigalpa (Honduras) the day of the solar eclipse with data obtained years before is presented along with an analysis of the measurements of the total geomagnetic field done in Amapala (Honduras), before and on 11 July, in order to detect any change associated to the event of the solar eclipse. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47013

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A morphological description of the solar photosphere, chromosphere, and the corona is presented from a complete sequence of visual and spectroscopic observations made in Honduras (Amapala), during the total solar eclipse of 11 July 1991 and from the analysis of some emission and absorption lines at all the eclipse phases. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47019

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

In this paper we present the results of an experiment performed to detect the total flux of muons incident over Tegucigalpa (Honduras) the day of the total solar eclipse of the 11 July, 1991; and also a comparison with data obtained before the eclipse and registered in the past years. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47014

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Possible variations of the total geomagnetic field coincident with the occurrence of the total solar eclipse of 11 July 1991 are presented and discussed here. Data obtained from the measurements done in Honduras (Amapala), before and during the total solar eclipse reveal that the day of the eclipse a drop on the average value of the total geomagnetic field from 38 982 Gammas (0.39 Gauss) to 7 000 Gammas (0.07 Gauss) occurred. This variation of the total geomagnetic field value is mainly associated to a possible change (a decrease) of the solar wind flux as detected from Earth within the path of totality. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47015

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Using an Eppley ‘Black and White’ pyranometer fitted with a shadow band and a digital recorder/printer, hourly diffuse solar irradiance Hdfalling on a horizontal surface at Ilorin, Nigeria has been measured from February to July 1993. The diffuse radiation data, after necessary correction for shadow band effect, were analyzed to obtain the diurnal and monthly variations of Hd. The highest daily total of diffuse radiation (Hdd) of value 4473±60 Wm−2day−1was recorded on the dust‐haze day and the lowest of value 2194±29 Wm−2day−1on a mostly overcast day. Similarly, the highest monthly average of daily total of diffuse radiation Hdm, of value 3237±43 Wm−2day−1was observed in April and the least of value 2872±34 Wm−2day−1in February. Also obtained are the diurnal and monthly variations of hourly values of Hd/H, where H is the corresponding hourly global irradiance measured separately by another instrument at the same location and time as Hd. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47016

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A brief account is given of on‐going measurements of solar and long‐wave radiation fluxes over Ile‐Ife (7.29°N, 4.34°E), Nigeria. Pyrheliometric measurements of direct solar radiation using an A˚ngstro¨m compensation Pyrheliometer were initially made over the 1984/85, 1985/86, and 1986/87 harmattan seasons. Then followed the establishment, in 1992, of a solar radiation monitoring station, capable of carrying out continuous measurement of global and diffuse solar radiation using Kipp and Zonen pyranometers, along with the long‐wave (sky) radiation using a pyrgeometer and, the photometric flux, using a LICOR LI‐210SA photometric sensor. Spectral measurements of solar radiation made over 300–1100 nm region using a LICOR LI‐1800 spectroradiometer of 6 nm resolution are discussed along with the relevant applications. The measurement efforts constitute a step towards the building up of a climatological data bank capable of meeting solar energy utilization demands as well as providing inputs for Climate and planetary boundary layer models and satellite remote sensing applications. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.47017

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Attention is drawn to two aspects of the study of binary stars: the determination of masses and absolute dimensions of the components, and the elucidation of non‐gravitational interactions between components. Some remarks are added about the possibilities of observing binaries with telescopes of 1‐m aperture or less. ©1994 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.46994

出版商:AIP    

年代:1995

数据来源: AIP