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Astron. Astrophys. 348, 993-999 (1999)

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4. Discussion and conclusions

The calculated solutions of the neutrino flux equations are consistent with the data of the neutrino detectors. I have shown that introducing the runaway energy source, it is possible to resolve the apparent contradiction between the different neutrino detectors even assuming standard neutrinos. Moreover, the results presented here suggest that the physical neutrino problems of the atmospheric neutrinos may be consistent with the solution of the solar neutrino problems even without introducing sterile neutrinos.

Considering the hypothetical activity-related changes of the solar neutrino fluxes, I found that the twofold energy source of the Sun produces different contributions in the different neutrino detectors. Apparently, it is the SuperKamiokande that is the most sensitive to the runaway processes. The contribution of the runaway neutrinos and the neutrinos of the standard-like quiet solar core runs in anti-correlation to each other. Therefore, their effects may largely compensate each other in the SuperKamiokande data. Nevertheless, it is indicated that intermediate and high-energy neutrinos may produce a slight correlation with the solar activity in the SuperKamiokande data since they correlate more closely with the runaway neutrino fluxes than with the neutrinos of the SSM-like solar core. They give a [FORMULA] of the total counts observed in the SuperKamiokande, therefore, the total flux may slightly correlate with the solar cycle. On the contrary, since the Homestake do not see the runaways, except the intermediate and high-energy electron neutrinos produced by the hot bubbles, its data may anti-correlate with the solar activity. Moreover, the dynamic solar model suggests that GALLEX data may anti-correlate with the solar cycle as well since it is more sensitive to the low-energy neutrinos arising from the proton-proton cycle, although it is also sensitive to the intermediate and high-energy electron neutrinos produced by the hot bubbles.

Now, obtaining indications of possible correlations between the solar neutrino fluxes and activity parameters, I can have a short look to the data whether they show or not such changes in their finer details. Such a marginal change may be indicated in the Fig. 3 of Fukuda et al. (1996). In this figure, the maximum value is detected just in 1991, at solar maximum, consistently with the results obtained here. Moreover, its value as read from that figure seems to be [FORMULA] of the value expected from the SSM. In 1995, in solar minimum, the lowest value, [FORMULA] is detected, again consistently with the interpretation we reached. Later on, the SuperKamiokande started to work and measured a value of [FORMULA] for the boron neutrino flux. Assuming that the values in 1995 and 1996-1997 did not differ significantly, as it is a period of the solar minimum, the two observation can be taken as equal, i.e. the [FORMULA] is equal with [FORMULA]. This method gives for the [FORMULA] value a boron flux of [FORMULA]. Now Bahcall et al. (1998b) developed an improved standard solar model, with significantly lower [FORMULA] cross sections, [FORMULA] instead of the previous [FORMULA] of Bahcall & Pinsonneault (1995). With this improved value the [FORMULA] leads to a [FORMULA]! This means that actually even the SuperKamiokande data may contain some, yet not noticed correlation tendency with the solar cycle. These indications make the future neutrino detector data more interesting to a possible solar cycle relation analysis.

The dynamic solar model has a definite suggestion that below 0.10 solar radius the standard solar model is to be replaced by a significantly cooler and possibly varying core. These predictions can be checked with future helioseismic observations. Helioseismology is not able to tell us the temperature in this deepermost central region. On the other hand, the presence of the thermonuclear micro-instabilities causes a significant departure from the thermal equilibrium and changes the Maxwell-Boltzmann distribution of the plasma particles. It is shown that such modification leads to increase the temperature of the solar core, which can compensate the non-standard cooling (Kaniadakis et al. 1996) and so the simple dynamic solar model can be easily consistent with the helioseismic results as well.

The indicated presence of a runaway energy source in the solar core - if it will be confirmed - will have a huge significance in our understanding of the Sun, the stars, and the neutrinos. This subtle and compact phenomena turns the Sun from a simple gaseous mass being in hydrostatic balance to a complex and dynamic system being far from the thermodynamic equilibrium. This complex, dynamic Sun ceases to be a closed system, because its energy production is partly regulated by tiny outer influences like planetary tides. This subtle dynamics is possibly related to stellar activity and variability. Modifying the participation of the MSW effect in the solar neutrino problem, the dynamic energy source has a role in the physics of neutrino mass and oscillation. An achievement of the suggested dynamic solar model is that it may help to solve the physical and astrophysical neutrino problems without the introduction of sterile neutrinos, and, possibly, it may improve the bad fit of the MSW effect (Bahcall et al. 1998a).

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© European Southern Observatory (ESO) 1999

Online publication: August 13, 199