It is believed that hydrogen is able to diffuse into the interior of the dwarf so that its surface density is reduced so that effectively helium begins to dominate. This would be analogous to a phase transition. But why would this take place only for the other side of the white dwarf and why such a sharp division to two regions.
Magnetic fields are proposed as a possible explanation.
- At the surface layer the magnetic fields tend to prevent the mixing of hydrogen and helium ions by forcing the ions to cyclotron orbits. The mixing argument of the article suggests that both hydrogen and helium are ionized.
- Whether this is the case depends on temperature. Wikipedia article claims that white dwarf temperatures are in the range 150,000 K-4000 K (15 eV -.1 eV). The upper limit 15 eV is slightly above 13.7 eV which is the ionization energy of hydrogen in ground state so that hydrogen could be ionized. Helium would not be ionized. If there is no ionization, the magnetic moment of hydrogen is what matters. Helium nucleus has a vanishing magnetic moment. Non-ionized helium looks magnetically inert but not hydrogen, which could also be at cyclotron orbits.
- The popular article informs that the temperature of the white dwarf is around 35,000 K (35 eV). For helium the ground state energy, proportional to Z2 is 54.8 eV which suggests that helium is not ionized and cyclotron orbits are not possible.
- If hydrogen is ionized, it moves along cyclotron orbits and tends to be magnetically confined. Also the higher magnetic field strength at the hydrogen side reduces the mixing. Since helium is not ionized, it is not magnetically confined and will mix more easily. This is true in the standard physics picture, in which one has no monopole flux tubes, which confine even non-charged particles.
- The higher value of the magnetic field implies a lower pressure and this would imply slower diffusion of the hydrogen to the interior. If the sum of the magnetic and ordinary pressures is constant, hydrogen oceans with a higher magnetic field strength and lower pressure could be formed.
- In the TGD framework, magnetic fields correspond to flux tubes and flux sheets. There are monopole flux tubes, something new, and ordinary flux tubes possible also in the Maxwellian world. There would be confinement inside the flux tubes. The flux tubes can also flatten to flux sheets.
- In particular, the gravitational magnetic monopole flux tubes and sheets are possible. This is a purely TGD based phenomenon. The gravitational Planck constant hbargr= GMm/β0 (β0= v0/c ≤ 1 is velocity parameter) is proportional to the mass M of the white dwarf and to the mass m of the particle, now helium or hydrogen.
- attaches only to/contains only particles with a fixed mass m,
- or whether it attaches to particles with varying mass m. If so, the gravitational Planck constant would be 2-particle property and depend on m for a gravitational flux tube/sheet associated with mass m.
What does the first option imply in the case of the weird white dwarf? One can consider two options.
- Monopole flux tubes form roughly parallel layers along the surface of the white dwarf. The layers associated with hydrogen and helium should be disjoint: but why?
- There are separate flux sheets associated with either hydrogen or helium but not both. If the flux sheets have boundaries orthogonal to the rotation axis, the hydrogen and helium layers are static. Since helium can mix in the tangential direction, it would prefer flux sheets. Hydrogen would not mix and could be also associated with flux tubes.
The interaction by cyclotron frequency resonance occurs only between charged particles with the same heff and the same flux tube field strength: this requires the same mass in the case of gravitational flux tubes. Note that one can also talk about electromagnetic Planck constant. This supports the library like organization.
Charged particles with different gravitational Planck constant (masses m) can have gravitational cyclotron energy resonance but not frequency resonance: this reflects Equivalence Principle.
For a summary of earlier postings see Latest progress in TGD.
For the lists of articles (most of them published in journals founded by Huping Hu) and books about TGD see this. .