# Stars/Sun/Neutrinos

< Stars‎ | Sun
This "neutrino image" of the Sun is produced by using the Super-Kamiokande to detect the neutrinos from nuclear fusion coming from the Sun. Credit: R. Svoboda and K. Gordan (LSU).

This laboratory is an activity for you to evaluate some possible origins of solar neutrinos. While it is part of the astronomy course principles of radiation astronomy, it is also independent.

Some suggested neutrino locational entities to consider are the core of the Sun, the chromosphere, a shell around the Sun above the photosphere, electromagnetic radiation, the neutrinos themselves, mass, time, Euclidean space, Non-Euclidean space, and spacetime.

More importantly, there are your locational or evaluative entities. And, yes, you can create as many as you need if you wish to.

You may choose to define your locational entities or use those already available.

Usually, research follows someone else's ideas of how to do something. But, in this laboratory you can create these too.

## Evaluation

Evaluation activity

Okay, this is an astronomy solar neutrinos laboratory, but you may create what an origin of solar neutrinos is.

Yes, this laboratory is structured.

I will provide an example of locating the origin of the neutrinos and an assessment of where they may be from. The rest is up to you.

Questions, if any, are best placed on the discussion page.

## Notations

You are free to create your own notation or use that already available.

## Control groups

For determining where the solar neutrinos are coming from, what would make an acceptable control group? Think about a control group to compare your method or your process of creating a method to.

## Proof of concept

The first concept that needs a proof is that neutrinos can originate from some process above the photosphere within about 2-4 solar radii.

"[N]eutrino flux increases noted in Homestake results [coincide] with major solar flares [14]."[1]

This result together with those in the next two sections establishes that neutrinos are being produced by processes above the photosphere and probably within 2-4 solar radii as most solar flares give off energy close to and into the chromosphere.

## Chromospheres

"The correlation between a great solar flare and Homestake neutrino enhancement was tested in 1991. Six major flares occurred from May 25 to June 15 including the great June 4 flare associated with a coronal mass ejection and production of the strongest interplanetary shock wave ever recorded (later detected from spacecraft at 34, 35, 48, and 53 AU) [15]. It also caused the largest and most persistent (several months) signal ever detected by terrestrial cosmic ray neutron monitors in 30 years of operation [16]. The Homestake exposure (June 1–7) measured a mean 37
Ar
production rate of 3.2 ± 1.5 atoms/day (≈19 37
Ar
atoms produced in 6 days) [13]; about 5 times the rate of ≈ 0.65 day −1 for the preceding and following runs, > 6 times the long term mean of ≈ 0.5 day−1 and > 2 1/2 times the highest rates recorded in ∼ 25 operating years."[1]

## Coronal clouds

This figure shows a detected 94 % correlation between scaled sunspot numbers and neutrino detections. Credit: John N. Bahcall.

The highest flux of solar neutrinos come directly from the proton-proton interaction, and have a low energy, up to 400 keV. There are also several other significant production mechanisms, with energies up to 18 MeV.[2]

The parts of the Sun above the photosphere are referred to collectively as the solar atmosphere.[3]

"Neutrinos can be produced by energetic protons accelerated in solar magnetic fields. Such protons produce pions, and therefore muons, hence also neutrinos as a decay product, in the solar atmosphere."[4]

"Energetic protons in the solar corona could explain Figure 2 [at right] only if (1) they tap a substantial fraction of the entire energy generated in the corona, (2) the energy generated in the corona is at least 3 times what has been deduced from the observations, (3) the vast majority of energetic protons do not escape the Sun, (4) the proton energy spectrum is unusually hard (p0 = 300 MeV c-1, and (5) the sign of the variation is opposite to what one would predict. As the likelihood of all of these conditions being fulfilled seems extremely small, we do not believe that neutrinos produced by energetic protons in the solar atmosphere contribute significantly to the neutrino capture in the 37
Cl
experiment."[4]

## Experiments

In the above section five criteria for the current neutrino flux are made available to assess the neutrino flux coming from above the photosphere:

1. energetic protons "tap a substantial fraction of the entire energy generated in the corona",[4]
2. "the energy generated in the corona is at least 3 times what has been deduced from the observations",[4]
3. "the vast majority of energetic protons do not escape the Sun",[4]
4. "the proton energy spectrum is unusually hard (p0 = 300 MeV c-1",[4] and
5. "the sign of the variation is opposite to what one would predict."[4]

In this section, each of these is examined using experimental results already available.

Here on the Earth's surface the νe flux is about 1011 νe cm-2 s-1 in the direction of the Sun.[5]

"The total number of neutrinos of all types agrees with the number predicted by the computer model of the Sun. Electron neutrinos constitute about a third of the total number of neutrinos. [...] The missing neutrinos were actually present, but in the form of the more difficult to detect muon and tau neutrinos."[5]

### Protons

The first piece of information that seems missing are the reactions that produce the higher energy neutrinos: νµ and ντ.

For antiproton-proton annihilation at rest, a meson result is, for example,

${\displaystyle p^{+}+{\bar {p}}^{-}\rightarrow \pi ^{+}+\pi ^{-},}$[6]
${\displaystyle {\pi }^{+}\rightarrow {\mu }^{+}+{\nu }_{\mu }\rightarrow e^{+}+{\nu }_{e}+{\bar {\nu }}_{\mu }+{\nu }_{\mu },}$[7] and
${\displaystyle D_{S}\rightarrow \tau +{\bar {\nu }}_{\tau }\rightarrow \nu _{\tau }+{\bar {\nu }}_{\tau }.}$[8]

"All other sources of ντ are estimated to have contributed an additional 15%."[8]

${\displaystyle \tau \rightarrow e+\nu _{\tau }+\nu _{e},}$[8]

for two neutrinos.[8]

${\displaystyle \tau \rightarrow h+\nu _{\tau }+X,}$[8]

where ${\displaystyle h}$ is a hadron, for two neutrinos.[8]

### Coronal heating

Based on the 3He-flare flux from the Sun's surface and Surveyor 3 samples (implanted 15N and 14C in lunar material) from the surface of the Moon, the level of nuclear fusion occurring in the solar atmosphere is approximately at least two to three orders of magnitude greater than that estimated from solar flares such as those of August 1972.[9]

Although 7Be is usually assumed to have been produced by the Big Bang nuclear fusion, excesses (100x) of the isotope on the leading edge[10] of the Long Duration Exposure Facility (LDEF) relative to the trailing edge suggest that fusion near the surface of the Sun is the most likely source.[1] The particular reaction 3
He
(α,γ)7
Be
and the associated reaction chains 7
Be
(e-e)7
L
(p,α)α and 7
Be
(p,γ)8
B
=> 2α + e+ + νe generate 14% and 0.1% of the α-particles, respectively, and 10.7% of the present-epoch luminosity of the Sun.[11] Usually, the 7
Be
produced is assumed to be deep within the core of the Sun; however, such 7
Be
would not escape to reach the leading edge of the LDEF.

### Coronal loops

The image shows solar coronal loops observed by the Transition Region And Coronal Explorer (TRACE), 171 Å filter. Credit: TRACE/NASA.
The image shows the cooling post-flare arcade (rotated by -90 degrees so that north is to the right) 6h after the flare (at 00:11 UT on September 8. Credit: TRACE/NASA.

"Almost as soon as Active Region 10808 rotated onto the solar disk, it spawned a major X17 flare. TRACE was pointed at the other edge of the Sun at the time, but was repointed 6 hours after the flare started. The image on the left shows the cooling post-flare arcade (rotated by -90 degrees so that north is to the right) 6h after the flare (at 00:11 UT on September 8); the loop tops still glow so brightly that the diffraction pattern repeats them on diagonals away from the brightest spots. Some 18h after the flare, the arcade is still glowing, as seen in the image on the right (at 11:42 UT on September 8). In such big flares, magnetic loops generally light up successively higher in the corona, as can be seen here too: the second image shows loops that are significantly higher than those seen in the first. Note also that the image on the right also contains a much smaller version of the cooling arcade in a small, very bright loop low over the polarity inversion line of the region."[12]

Nearly all of the TRACE images of coronal loops and the transition region indicate that material in these loops and loop-like structures returns to the chromosphere.

"Normally, solar energetic particle (SEP) events associated with disturbances in the eastern hemisphere are characterized by slow onset and lack of high-energy particles. The SEP event associated with the first major flare (X17) [...] is among very few such events over several decades in that although the source region was on the east limb, the particle flux started to rise only a few hours from the flare onset, while the flux of protons with energies in excess of 100 MeV went up by more than a factor of one hundred. We do not understand how these energetic particles can reach the Earth from that side of the Sun, because there should be no magnetic connectivity."[12]

### Solar cycles

As the above sections suggest, the amount of hardness of the proton spectrum may be partially met by the accelerator-like activity of the coronal loops during most of the solar cycle.

Perhaps even more important is the strong correlation of the four near-zero neutrino detections with no scatter at the sunspot minimum. Is it the case that few if any neutrinos are produced at sunspot minimum or solar cycle minimum?

### Sign of variation

While more information is needed, it may be the case that both νµ and ντ need not be oscillation products but may occur with or without oscillation as a normal decay product. Initial detection of these other two neutrinos help to confirm the neutrino flux predictions for the Standard Solar Model.

Since the standard solar model was composed using information derived from accelerator experiments, it may be inherent to its design to reflect the neutrino production of the particle accelerators in the coronal clouds around the Sun.

The emission of neutrinos from the solar octant may coincide with the solar cycle, be anti-correlated, or independent.

## Results

The coronal heating section suggests that the energy sufficient for the fusion believed to be going on in the core of the Sun may actually be present above the photosphere.

As the coronal clouds are believed to regenerate themselves quite readily the vast majority of energetic protons may escape and be readily replaced to continue the fusion. But, this suggests that additional energy may be coming from somewhere else.

The hardness of the proton spectrum may be amplified by the accelerating magnetic fields.

Any sign of variation may not be relevant unless it directly relates to the solar cycles, e.g., solar cycle maximum is solar neutrino maximum, solar minimum is solar neutrino minimum.

Since the standard solar model was composed using information derived from accelerator experiments, it may be inherent to its design to reflect the neutrino production of the particle accelerators in the coronal clouds around the Sun.

## Discussion

The experimental evidence discovered so far suggests the likelihood that most or all neutrinos may be produced above the photosphere. This may be accomplished in many different ways. In turn, these alternatives allow each endeavor to have impact and potential.

The large factors of 2 1/2 to 6 times the neutrino production rate suggests that much less energy is needed to produce the neutrino level of a quiet Sun.

The large amounts of fusion that has evidenced itself in the section on coronal heating is receiving its energy from somewhere. Probably not from internal sources.

## Conclusions

It may be that the neutrinos that emanate from the solar octant come from above the Sun as part of a response to an interstellar flow that heats the Sun externally.

## Report

Title

Neutrinos from Around the Sun

by --Marshallsumter (discusscontribs) 04:19, 12 March 2014 (UTC)

Abstract

Experimental evidence has been gathered together to suggest that most and perhaps all neutrinos detected from the solar octant emanate from a shell around the Sun rather than from the core of the Sun. Lines of analysis exist for examining this contention to determine its validity or its shortcomings.

Introduction

Although neutrinos may originate from inside the Sun, it is equally likely and maybe more so that external heating of the Sun by an interstellar electron influx energizes the coronal cloud that in turn creates neutrinos in an apparent relentless heating of the gas cloud that is the Sun. From earlier correlations between the solar cycle and the planets it may be also that the sunspot cycle relates to electron flows from the planets that intensify the neutrino production.

Experiment

The experimentation consists of trying to organize what experimental evidence exists into sections to address the concerns described as necessary to show that neutrinos come from above and around the Sun.

This allows others to alter or improve to determine if the idea of external heating has more merit than gravitational collapse.

The experiments consist of at least five parts:

1. energetic protons,
2. coronal energy,
3. proton escape,
4. proton hardness, and
5. sign or oscillatory variation.

Results

The organization appears to be complimentary to the idea that external heating drives external fusion. How the influx of electrons brings about the solar cycle and the variations in the neutrino flux is suggested. The outflux of the fast and slow solar wind may be an insufficient loss of energetic protons to reduce or prevent surface or chromosphere fusion processes.

Discussion

Many formula details have not been described to present a complete picture of the heating process and how this electron influx produces the various magnetic and electric manifestations observed.

That each type of neutrino can occur depending on the subatomic particle interactions may be good news for contributors.

Conclusion

A preliminary outline has been suggested of how the heating of the Sun is being accomplished.

## Evaluation

To assess your idea on how to determine where the neutrinos are coming from, including your justification, analysis and discussion, I will provide such an assessment of my example for comparison.

Evaluation

Probably the major shortcoming is the details of the mechanism for solar heating itself and how it spheres the Sun.

## Hypotheses

1. Most and probably all neutrinos originating from the solar octant originate from the chromosphere and above, including the coronal clouds.

## References

1. Maurice Dubin and Robert K. Soberman (April 1996). "Resolution of the Solar Neutrino Anomaly". arXiv: 1-8. Retrieved 2012-11-11.
2. A. Bellerive, Review of solar neutrino experiments. Int.J.Mod.Phys. A19 (2004) 1167-1179
3. K.D. Abhyankar (1977). "A Survey of the Solar Atmospheric Models". Bull. Astr. Soc. India 5: 40–44.
4. J. N. Bahcall and G. B. Field and W. H. Press (September 1, 1987). "Is solar neutrino capture rate correlated with sunspot number?". The Astrophysical Journal 320 (9): L69-73. doi:10.1086/184978. Retrieved 2013-07-07.
5. John N. Bahcall (April 28, 2004). "Solving the Mystery of the Missing Neutrinos". Nobel Media AB. Retrieved 2014-03-08.
6. Eberhard Klempt, Chris Batty, Jean-Marc Richard (July 2005). "The antinucleon-nucleon interaction at low energy: annihilation dynamics". Physics Reports 413 (4-5): 197-317. doi:10.1016/j.physrep.2005.03.002. Retrieved 2014-03-09.
7. Eli Waxman and John Bahcall (December 14, 1998). "High energy neutrinos from astrophysical sources: An upper bound". Physical Review D 59 (2): e023002. doi:10.1103/PhysRevD.59.023002. Retrieved 2014-03-09.
8. K. Kodama, N. Ushida1, C. Andreopoulos, N. Saoulidou, G. Tzanakos, P. Yager, B. Baller, D. Boehnlein, W. Freeman, B. Lundberg, J. Morfin, R. Rameika, J.C. Yun, J.S. Song, C.S. Yoon, S.H.Chung, P. Berghaus, M. Kubanstev, N.W. Reay, R. Sidwell, N. Stanton, S. Yoshida, S. Aoki, T. Hara, J.T. Rhee, D. Ciampa, C. Erickson, M. Graham, K. Heller, R. Rusack, R. Schwienhorst, J. Sielaff, J. Trammell, J. Wilcox, K. Hoshino, H. Jiko, M. Miyanishi, M. Komatsu, M. Nakamura, T. Nakano, K. Niwa, N. Nonaka, K. Okada, O. Sato, T. Akdogan, V. Paolone, C. Rosenfeld, A. Kulik, T. Kafka, W. Oliver, T. Patzak, and J. Schneps (April 12, 2001). "Observation of tau neutrino interactions". Physics Letters B 504 (3): 218-24. Retrieved 2014-03-10.
9. Fireman EL, Damico J, Defelice J (March 1975). Solar-wind tritium limit and nuclear processes in the solar atmosphere, In: Lunar Science Conference Proceedings 6th Houston TX. 2. New York: Pergamon Press, Inc.. pp. 1811–21. Retrieved 2014-03-11.
10. Fishman GJ, Harmon BA, Gregory JC, Pamell TA, Peters P, Phillips GW, King SE, August RA, Ritter J, Cuichin JH, Haskins PS, McKisson JE, Ely D, Weisenberger AG, Piercey RB, Dybler T (February 19991). "Observation of 7Be on the surface of LDEF spacecraft". Nature 349 (6311): 678-80. doi:10.1038/349678a0.
11. Krčmar, M.; Krečak, Z.; LjubičiĆ, A.; Stipčević, M.; Bradley, D. A. (December 2001). "Search for solar axions using 7
Li
"
. Physical Review D (Particles and Fields) 64 (11): 115016-9. doi:10.1103/PhysRevD.64.115016. Retrieved 2014-03-11.

12. Fred Espenak (September 8, 2005). "Images of the Sun taken by the Transition Region and Coronal Explorer". Palo Alto, California USA: Stanford-Lockheed Institute for Space Research and NASA Small Explorer program. Retrieved 2014-03-11.