Diffusion Limit of the Lorentz Model: Asymptotic Preserving Schemes Christophe Buet, Stéphane Cordier, Brigitte Lucquin-Desreux and Simona Mancini ESAIM: M2AN, 36 4 (2002) 631-655 Published online: 15 September 2002 DOI: 10.1051/m2an:2002028