LWS TR&T Focus Teams:

Low-To Mid-Latitude Ionospheric Irregularities and Turbulence

Team Leader: Joe Huba (NRL)
Team Research Plan:
Next Team Meeting: TBD
Team-Maintained Web Site: TBD
Team Publications: TBD
Team Members:
David Fritts (Northwest Research Associates)
David Hysell (Cornell)
Thomas Immel (Cal Berkeley)
Endawoke Kassie (Boston College)
Meers Oppenheim (Boston U)

Target Description: The ionosphere plays a major role in space weather due to its important influence on the propagation of electromagnetic waves. Changes in this propagation can significantly impact communication and navigation systems primarily through the development of electron density irregularities and plasma turbulence, often in the vicinity of large electron density gradients. Associated irregularities and turbulence can have a spatial range from tens of kilometer through centimeter scales and temporal scales from milliseconds to tens of minutes. A wide variety of physical processes occur on these separate scales and, for decades, this has posed a considerable challenge to the goal of a truly self-consistent, comprehensive model-based understanding of irregularity dynamics and morphology.

However, recent developments have presented new opportunities to make large advances in our understanding of irregularity physics. Large observational databases from ground based radar and satellite platforms (e.g. Jicamarca radar, SuperDARN HF radar, DMSP, C/NOFS, DEMETER, GPS TEC) are available for a wide range of appropriate irregularity scale sizes. For example, recent observations by the C/NOFS spacecraft provide unprecedented measurements of the equatorial ionosphere that enable timely, high-resolution studies of ionospheric irregularities. Total electron content (TEC) measurements between the CERTO beacon and a ground network of receivers near Jicamarca Radio Observatory provide the unprecedented opportunity of imaging the genesis of equatorial plasma instabilities and scintillation at high spatial resolution and study the onset, evolution, and propagation of these irregularities. Moreover, recent advances in modern computer technology; kinetic and fluid models with sophisticated, realistic boundary conditions; and high resolutions have recently become available. A focused team effort to apply these new tools, constrained appropriately by observations, is timely and has significant potential to transform our knowledge of irregularities and advance our predictive space weather capabilities for their presence and effects.

Goals and Measures of Success: The goals of this FST are to provide an improved understanding and a predictive capability of ionospheric irregularities and turbulence, and specifically, to identify the causal mechanisms of the irregularities based on theoretical and computational studies in conjunction with comparison to experimental data. Measures of success are the following: Development of improved models of E and F region plasma instabilities and turbulence; Establishment of the connection (if any) between E and F region irregularities; Identification of the causes of day-to-day variability of irregularities; Understanding of the connection between large-scale ionospheric processes and the development of electron density irregularities (e.g., equatorial spread F); and € Development of a predictive capability for irregularity onset and evolution.

Types of Investigations:

• Theoretical studies of the linear and nonlinear development of ionospheric instabilities;
• First-principle modeling of ionospheric irregularities and turbulence in 2D and 3D (e.g., fluid, hybrid, PIC simulation models);
• Observational studies identifying regions of ionospheric irregularities and possible causal mechanisms; and
• Characterization of irregularities and turbulence as a function of geophysical parameters (e.g., latitude, longitude, altitude, F10.7, geomagnetic storm conditions etc.).