Storm‐induced plasma stream in the low‐latitude to midlatitude ionosphere

Abstract

[1] Geomagnetic disturbances from 7 to 12 November 2004 were quite intense, and the maximum excursion of Dst reached -374 nT. Unusual ionospheric phenomena have been observed around the world that have been associated with successive magnetic storms during this period. The ionospheric total electron content (TEC) was increased at the longitudes of Japan within a short time after sunset on 8 November, from 20 TEC units at 1830 JST to 97 TEC units at 2015 JST (JST = UT + 9 h), where 1 TEC unit = 1 10 16 el/m 2 . The enhanced TEC was significant over Hokkaido ( 43 ı N), and the center of the enhanced region was well within the plasmasphere as an L value of approximately 1.5. The drift velocity of the plasma in the density-enhanced region measured by the Defense Meteorological Satellite Program (DMSP) satellite was westward with a peak value of 250 m/s in the Earth's frame, demonstrating a positive correlation between density and drift velocity. A similar TEC event was observed after sunset on 10 November: TEC was enhanced, from 15 TEC units at 1830 JST to 45 TEC units at 2030 JST. During the second event, the ionosphere was highly structured and the rate of the TEC index (ROTI) increased. The two-dimensional map of a ROTI-enhanced region exhibited the west to northwest transportation of plasma in which density irregularities were entrained. A physical mechanism is proposed to explain these disturbances, i.e., storm-induced plasma stream, which is different from a phenomenon called storm-enhanced density at midlatitudes.Citation: Maruyama, T., G. Ma, and T. Tsugawa (2013), Storm-induced plasma stream in the low-latitude to midlatitude ionosphere,

Effects of solar cycle 24 activity on WAAS navigation

“…An important difference between this phenomenon and the SED/tongue of ionization is that the SED and plume are typically considered daytime phenomena, whereas this feature spans the midlatitudes after local sunset. It is not limited to the American sector [ Maruyama et al , ] but tends to manifest around Florida when observed in North America.…”

A new ionospheric storm scale based on TEC and foF2 statistics

“…The downward arrow indicates the largest TEC , i.e., 23.9 at 13 UT (22 JST) during the recovery phase of the geomagnetic storm. This TEC enhancement has been investigated in many papers [e.g., Maruyama , ; Nishioka et al , ; Maruyama et al , ]. Maruyama et al [] suggested that the extreme TEC enhancement observed in Japan could be caused by the storm‐induced plasma stream in which a combination of prompt penetration electric fields and disturbance dynamo electric fields plays an important role.…”

“…This TEC enhancement has been investigated in many papers [e.g., Maruyama , ; Nishioka et al , ; Maruyama et al , ]. Maruyama et al [] suggested that the extreme TEC enhancement observed in Japan could be caused by the storm‐induced plasma stream in which a combination of prompt penetration electric fields and disturbance dynamo electric fields plays an important role. Another I P 3 event appeared during the successive geomagnetic storm on 10 November.…”

Topside ionospheric irregularities as seen from multisatellite observations

“…It should be noted that the ROT/ROTI technique by the ground-based GPS observations is widely used to track signatures of the ionospheric irregularities and their influence on the performance of navigation systems [e.g Pi et al, 1997;Aarons and Lin, 1999;Nishioka et al, 2008;Maruyama et al, 2013;Cherniak et al, 2014;Astafyeva et al, 2014]. Results of the ROTI technique applied to LEO GPS observations were not yet reported.…”