SA032-03
On multi-scale density irregularities observed by sounding rockets within regions of enhanced scintillations in the cusp ionosphere
Tuesday, 15 December 2020: 10:08
Virtual
Andres Spicher1, James W Labelle2, John W Bonnell3, Scott R Bounds4, Francesca Di Mare1, Stephen A Fuselier5, Yaqi Jin1, Craig Kletzing4, Kjellmar Oksavik6,7, Wojciech J. Miloch1, Joran Moen1,7, Chrystal Moser2, Roger Roglans3, Rhyan Sawyer5,8 and Toru Takahashi1,9, (1)University of Oslo, Department of Physics, Oslo, Norway, (2)Dartmouth College, Department of Physics & Astronomy, Hanover, NH, United States, (3)University of California, Berkeley, Space Sciences Laboratory, Berkeley, CA, United States, (4)University of Iowa, Iowa City, IA, United States, (5)Southwest Research Institute, San Antonio, TX, United States, (6)University of Bergen, Bergen, Norway, (7)University Centre in Svalbard, Longyearbyen, Norway, (8)University of Texas at San Antonio, Physics and Astronomy, San Antonio, TX, United States, (9)National Institute of Maritime, Port and Aviation Technology, Electronic Navigation Research Institute, Tokyo, Japan
Abstract:
At high latitudes, plasma density irregularities causing Global Navigation Satellite System (GNSS) phase scintillations are common, and they generally peak around the cusp and auroral regions. As the physical causes for the creation of the irregularities are still unclear, characterizing density structures and their sources is essential to develop models of scintillations. With their extensive set of instruments providing high-resolution measurements, sounding rockets can provide invaluable insights into plasma structuring, especially at small scales.
The Twin Rockets to Investigate Cusp Electrodynamics 2 (TRICE-2) consisted of two sounding rockets launched on 08 December 2018 from Andøya, Norway. Both rocket payloads intersected an active cusp with regions of enhanced GNSS phase scintillations observed from the ground. Inspection of the high-resolution (10 kHz) electron density obtained onboard TRICE-2 by the multi-needle Langmuir probe system reveals the presence of a hierarchy of intermittent irregularities spanning tens of kilometers to a few meters. Characterization and multi-scale analysis of the electron density fluctuations are presented and, by comparing with other in-situ datasets such as electric field, magnetic and particle precipitation data, the possible sources for irregularity creation are discussed. In particular, the largest fluctuations observed by both rockets were located on the poleward edge of the cusp in regions of fast inhomogeneous flow, supporting the view that sheared flows are of significant importance, and that large-scale inhomogeneities may provide a background for the growth of micro-scale structures.
This study provides insights into the nature of cusp density irregularities and valuable inputs to constrain models and advance our understanding of density irregularities and their underlying processes.
