Axion Emission by Magnetic-Field Induced Conversion of Longitudinal   Plasmons
  Magnetic fields mix axions with photons, allowing for the cyclotron process e -> e + a by virtue of an intermediate plasmon even if axions do not couple to electrons at tree level. The axion and longitudinal-plasmon dispersion relations always cross for a certain wave number, leading to a resonant enhancement of this process. Even then, however, it cannot quite compete with the usual nucleon processes in a supernova core. The well-known axion window 10^{-5} eV < m_a < 10^{-2} eV remains open and axions may still constitute the cosmic dark matter. 
N.V.Mikheev (Yaroslavl Univ.), G.Raffelt (MPP, Munich),   L.A.Vassilevskaya (Lomonosov Univ., Moscow)