Magnetic Storm Effects on the Occurrence and Characteristics of Plasma Bubbles

• Published in: Journal of geophysical research. Space physics Vol. 128; no. 11
• Main Authors: Adhya, P., Valladares, C. E.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-11-2023
• Subjects: Atmosphere; bubble depth; bubble internal vertical velocity; Bubbles; C/NOFS; equatorial plasma bubbles; equatorial spread F; Geomagnetic storms; Geomagnetism; Ion velocity; Ionospheric conditions; Irregularities; Magnetic effects; Magnetic storms; Magnetospheres; Navigation systems; Plasma; Plasma bubbles; Solar minimum; Storm effects; Storms; Upper atmosphere; Velocity
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2023JA031292

The Communications/Navigation Outages Forecast System satellite mission was designed to investigate the ionospheric conditions that lead to the formation of irregularities. Here, we have studied the effect of magnetic storms on the formation and evolution of plasma bubbles during the satellite's lifetime (2008–2015). During this period encompassing solar minimum and maximum conditions, many magnetic storms of varying intensity developed, producing a unique and rich data set of 248 storms (14 intense, 69 moderate, and 165 weak) that occurred during the same timeframe to examine the role of external magnetospheric drivers in the production and dynamics of equatorial plasma bubbles. We have used the Planar Langmuir Probe and Ion Velocity Meter instruments to elucidate the role of magnetic storm intensity on the bubble's depth, internal speed, width, occurrence, and lifetime. The pre‐reversal enhancement (PRE) tends to increase during the main phase and when BZ is southward. New bubbles occur during large excursions of the PRE value. The bubble lifetime extends and remains active during the main and part of the recovery phase. The plasma velocity within the bubbles increases and typically becomes over 100 m/s during significant PRE and BZ negative times. The depth of bubbles reaches values close to 100% during intense storms. In general, the intensity of the storms seems to control and augment the plasma bubbles' depth, width, and internal velocity.
Plain Language Summary
Plasma irregularities, known as plasma bubbles, have been studied for several decades. Ongoing studies of plasma bubbles include the investigation of background conditions and events such as geomagnetic storms (disturbances in the upper atmosphere caused by southward IMF) that lead to the production and growth of plasma bubbles. Our work focuses on the formation of plasma bubbles that developed during several geomagnetic storms of varying intensities that occurred within 7 years, encompassing solar minimum and maximum. Changes in the production time, count, structure, and lifetime of bubbles were observed during the most important period of storms accompanying the increased evening‐time upward speed of the background plasma. These changes are consistent with studies based on the impact of geomagnetic storms on the upper atmosphere. The results provide an insight into the timeframe for bubble production, structural growth, and decay during the duration of the storms.
Key Points
We analyzed bubble characteristics during magnetic storms that occurred between May 2008 and April 2014
New bubbles that develop during the initial, main, or early recovery phase of storms don’t decay until dawn
Bubble depths and vertical bubble velocities enhance during storms' initial, main, or early recovery phase