Difference in the current-voltage relationships between dawn and duskside inverted-V events

We analyze 81 Freja inverted-V events to study the current-voltage relation ship in different magnetic local time sectors. We use data from the F7 (TES P) electron detector. The events are categorized according to the current-v oltage relationship so that in categories named U, C, and O the current j i ncreases, is constant, or decreases with the voltage V, respectively. We fi nd that the U and C categories are the most common on the eveningside, whil e the O category dominates the morningside. Globally, category U is the lea st common. Besides the current density, we also study the behavior of the s ource plasma density and temperature as a function of the voltage in each c ategory and find that source plasma density is nearly constant in U categor y, decreases slightly in C, and decreases strongly in O. The source plasma temperature is linearly correlated with the voltage and behaves rather unif ormly in all categories. We suggest that there may be an important physical difference between morningside and eveningside inverted-V events and discu ss possible explanations in terms of different auroral potential structure models.