Trajectories of the acoustic waves in the Sun.

Several thousand modes were detected precisely on the surface of the Sun. Every mode of vibration propagates according to a different "path" in the Sun.
The blue lines correspond to modes of low degree penetrating profoundly into the star, the red lines correspond to superficial modes, of high degree.
Source: Saclay-CEA-SAP
And to know more about it:
Structure interne & Sismologie. (Benoît Mosser - Obs Paris)

Sunspots.
http://antwrp.gsfc.nasa.gov/apod/ap031027.html

Known from - 800 by the Chinese astronomers (Book of the changes), they will be known in Europe only from the century of Galilee.

Sunspots and magnetism.
The dark sunspots are accompanied by white sunspots. Between these dark and white spots exist magnetic fields.
http://antwrp.gsfc.nasa.gov/apod/ap991024.html
http://antwrp.gsfc.nasa.gov/apod/ap980616.html

Cycle of Wolf and Associated phenomena

1. Sunspots always appear between 35^oN and 35^oS of sun's latitude and move, during time, up to the equator (law of Schperer), in a belt called "the royal zone".

2.  The period of a cycle is on average 11 years. As adjacent periods are partially superimposed, the sum of two periods is less than 22 years. (Approximately 18 - 19 years).

3. From one period to the next, the magnetic fields, between spots, are reversed.

4. The number of spots varies during the Cycle of Wolf and at the same rhythm as this one.

5. The diameter of the sun would vary at the rate of 2 Wolf cycles. (It is a weak phenomenon of the order of Δd = 1 to 2 km, as compared with the diameter of the sun, D = 1,392.106 Km, and thus very difficult to observe.
   Note that there would also be variations of diameter of lower periods (320 to 1000 days), but these do not seem to have any direct link with the Wolf Cycle. For more information see:
   Drift-Time Measurements of the Solar Diameter 1990-2000: New limits on Constancy.
   But this study covers only a period of less than 10 years. Thus, it does not allow us to draw any positive conclusions on the subject.
   

 
What is the logical link of all these phenomena?

1. Sunspots are certainly only a side effect due to the convection in the convective zone of the Sun and to the associated magnetic fields (MHD).
   http://antwrp.gsfc.nasa.gov/apod/ap011108.html
   http://antwrp.gsfc.nasa.gov/apod/ap970904.html

2.  These sun magnetic fields do not seem to be able, by themselves, to cause all the observed phenomena. And especially they cannot explain the period of the Wolf cycle.

3.  Acoustic resonances of approximate period of 22 years cannot be explained by the geometry and physics of the Sun. The speeds of these waves do not allow it.

4. On the other hand the variations of the sun's diameter could be the cause of all the described phenomena.
   Indeed the increase of the diameter of the sun during approximately 11 years, followed by its decrease during the same duration, could not be the cause of the inversions of the spin of the convection  columns, due to the forces of Coriolis, followed by the inversion of electric currents and finally inversions of magnetic fields.

5.  But could not these variations of sun diameter be only an intermediate phenomenon masking something more fundamental ?
   What is the cause of these periodic variations of the sun's diameter?

6. And especially, what diameter does it involves?

 
The Great Galactic Gong (GGG)
 

1.  A very big Gravitational Wave, of period twice 11 years (approximately 22 years), could be at the origin of the periodic variations of the diameter of the Sun. (We shall call it the Great Galactic Gong - GGG).

2. Considering the speed of the gravitational waves (speed of light), its wavelength then would be 22 ly.

3. The Sun would thus behave as a Gigantic Weber Detector ! In other words as a detector of gravitational waves.

4. The source of these gravitational waves could be in the heart of the Galaxy (Pair of black holes in interaction?)

5.  If we admit that the galactic centre is approximately 30.000 ly from the solar system and if we take for standard distance/scales the wavelength of the GGG, we have only 30000 / 22, so be it 1363 periods! This is a relatively small number of oscillations. The oscillations cannot therefore undergo any weakaning or any perceptible red shift.
   Its sensitivity would be of the order of Δd / D, therefore 1 km/1,4.106 Km, thus on the order of 10^-6 ! That is infinitely superior to what Weber could expect from his small cylinder, and also infinitely superior to what we are entitled to hope from current interferometer experiments such as Virgo. (On the order of 3.10^-23 for arms equivalent to 100 km).

6. All the stars and planets of our galaxy would be subjected to the influence of these gravitational waves and could be used for detecting the waves.
   If this proposition is correct, then we can make a prediction: all the stars of the Galaxy obey the same cycle of Wolf as the sun, that is approximately twice 11 years. (The current resolution of instruments does not allow this detection as yet).

7. For all the stars of the Milky Way, the wavelength of the GGG is the same, only the relative phases differ.

8. There would therefore be a gravitational coupling between the heart of the galaxy and all the stars of the galaxy. This property would be generalized for all the galaxies.

1. The theory asserts that the period of the gravitational waves would be situated rather around 1ms ( 1000 Hz), and certainly not around 22 light years !

2.  How could the gravitational waves act and be detected on a very dilute gas mass, especially at the level of the photosphere ?

1. This is forgetting a little too quickly,

1. That the theory of interactive black holes is far from being complete.

2. That nobody has ever detected directly the slightest gravitational wave.

3.  That these waves, according to the theory, can be low frequencies modulated according to very particular modes which look a little like those which the radioelectricians call with acronyms "AM" and "BLU".

4. And in this case, it is this modulation which would be detected by the sun. The physics of this detection is yet to be discovered.

2. Nothing says to us that the gravitational waves would be active only at the level of the photosphere. They would be especially in the central regions of the sun where the density of matter is sufficient, very probably in the core. And thus it would be the variations of the diameter of the core, that would lead the Wolf Cycle. Let us note that the required observations are much more difficult.
   We can add that considering the dimension of the core of the sun relative to that of the GGG, the "detector thus composed" is totally aperiodic. It cannot enter in resonance. (And this would be true for all the stars). Let us note that if a star entered in resonance with a GGG, it would explode.
   
   
   Nothing says to us that the gravitational waves are active at the level of the photosphere. They would be active only in the central regions of the sun, where the density of matter is sufficient, very probably in the core. And thus it would be the variations of the diameter of the core, that would lead the Cycle of Wolf. Let us note that it result that the observations are very more difficult.
   We can add that considering the dimension of the core of the sun face to face of the GGG, the "detector so constituted" is totally aperiodic. He cannot enter in resonance. (And it would be true for all the stars).   Let us note that if a star entered in resonance with a GGG, it would explode.