Explore The Axion Dark Matter Through The Radio Signals From Magnetic White Dwarf stars

Axion as one of the promising dark matter candidates can be detected through narrow radio lines emitted from the magnetic white dwarf stars. Because of the existence of the strong magnetic field, the axion may resonantly convert into the radio photon (Primakoff effect) when it passes through the corona of the magnetic white dwarf, where the photon effective mass is equal to the axion mass. We show that for the magnetic white dwarf WD 2010+310, the future experiment SKA phase 1 with 100 hours of observation will set an upper limit on the axion-photon coupling $g_{a\gamma}$ of $\sim 10^{-12}~ \text{GeV}^{-1}$ for the axion mass range of $2 \times 10^{-8} \sim 10^{-6} $ eV.