Diurnal variations of Titan's ionosphere - Cui,J; Galand,M; Yelle,RV; Vuitton,V; Wahlund,J-E; Lavvas,PP; Mueller-Wodarg,ICF; Cravens,TE; Kasprzak,WT; Waite,JH (JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2009)