Dayside/nightside auroral X ray emission differences - implications for ionospheric conductance

被引:15
作者
Petrinec, SM
Imhof, WL
Chenette, DL
Mobilia, J
Rosenberg, TJ
机构
[1] Lockheed Martin Adv Technol Ctr, Dept L9 42 B255, Palo Alto, CA 94304 USA
[2] Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA
关键词
D O I
10.1029/2000GL000056
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
In this study we examine the occurrence probability of intense X ray emissions (>2 keV) from the auroral ionosphere in daylight and in darkness. The Polar Ionospheric X ray Imaging Experiment (PIXIE) on board the NASA/GGS Polar spacecraft remotely images the Earth's ionosphere from high altitude (apogee of about 9 Earth radii). This instrument is capable of observing the entire northern auroral region at once, and is normally unaffected by scattered sunlight; resulting in an unbiased study of differences in auroral emissions between daylight and darkness. The differences in the occurrence probability between daylight and darkness are interpreted as being due to differences in the local ionospheric conductivity as described in previous studies using in situ, particle populations and lower energy ionospheric emissions. There is also a clear dependence upon season which is in accordance with the Russell-McPherron effect. Under similar geomagnetic conditions, comparisons of occurrence probability separated by whether each region is in daylight or in darkness illustrate that intense auroral emissions are consistently more likely when a given region is in darkness than when the same region is in daylight.
引用
收藏
页码:3277 / 3279
页数:3
相关论文
共 7 条
[1]   The seasonal variation of auroral ion beams [J].
Collin, HL ;
Peterson, WK ;
Lennartsson, OW ;
Drake, JF .
GEOPHYSICAL RESEARCH LETTERS, 1998, 25 (21) :4071-4074
[2]   THE POLAR IONOSPHERIC X-RAY-IMAGING EXPERIMENT (PIXIE) [J].
IMHOF, WL ;
SPEAR, KA ;
HAMILTON, JW ;
HIGGINS, BR ;
MURPHY, MJ ;
PRONKO, JG ;
VONDRAK, RR ;
MCKENZIE, DL ;
RICE, CJ ;
GORNEY, DJ ;
ROUX, DA ;
WILLIAMS, RL ;
STEIN, JA ;
BJORDAL, J ;
STADSNES, J ;
NJOTEN, K .
SPACE SCIENCE REVIEWS, 1995, 71 (1-4) :385-408
[3]   Synoptic auroral distribution: A survey using polar ultraviolet imagery [J].
Liou, K ;
Newell, PT ;
Meng, CI ;
Brittnacher, M ;
Parks, G .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1997, 102 (A12) :27197-27205
[4]   Relation to solar activity of intense aurorae in sunlight and darkness [J].
Newell, PT ;
Meng, CI ;
Wing, S .
NATURE, 1998, 393 (6683) :342-344
[5]   Suppression of discrete aurorae by sunlight [J].
Newell, PT ;
Meng, CI ;
Lyons, KM .
NATURE, 1996, 381 (6585) :766-767
[6]  
RUSSELL CT, 1973, J GEOPHYS RES, V78, P98
[7]   BREMSSTRAHLUNG IN ATMOSPHERE AT SATELLITE ALTITUDES [J].
SELTZER, SM ;
BERGER, MJ .
JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS, 1974, 36 (07) :1283-1287