On a thermodynamic origin of the cometary ion rays

The generation of symmetric pairs of narrow ion rays in cometary plasma tails has long been a challenging problem in cometary physics. In addition to (a) the dynamical responses of the cometary ionospheres to the time variations in the solar wind and (b) the possibility of enhanced ionization in the central coma as a result of an aurora-like process, it is proposed here that a modulation of the condition of electron heat conduction along the magnetic flux tubes draped around the inner coma could also produce an important change in the electron temperature profile and hence the dimension of the ion source region. This new mechanism can be further examined by coordinated optical spectroscopic and imaging observations from the ground.