Nonlinear wave propagation and reconnection at magnetic X-points in the Hall MHD regime J. Threlfall, C. E. Parnell, I. De Moortel, K. G. McClements and T. D. Arber A&A, 544 (2012) A24 Published online: 19 July 2012 DOI: 10.1051/0004-6361/201219098