ULF waves from the ionosphere to the outer planets

Kivelson, M. G.

doi:10.1029/169gm04

Cited by 21 publications

(14 citation statements)

References 56 publications

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“…Generally speaking, Earthward-moving fast flows have been attributed to either a reconnection process in the magnetotail or to some other plasma sheet instability (e.g., Sergeev et al 1992). Kivelson (2006) mentioned several possibilities that could control periodicity but none of them has been confirmed yet. For example, compressional waves, launched at the reconnection site, reflect back either from a region near Earth or the magnetopause and act on the reconnection site by quenching the reconnection process temporarily; or a kinetic tearing mode instability may have a spatial structure that imposes a temporal structure on the flows when observed from a fixed point in space.…”

Section: Modelmentioning

confidence: 97%

Review of Pi2 Models

2011

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More than half a century after the discovery of Pi2 pulsations, Pi2 research is still vigorous and evolving. Especially in the last decade, new results have provided supporting evidence for some Pi2 models, challenged earlier interpretations, and led to entirely new models. We have gone beyond the inner magnetosphere and have explored the outer magnetosphere, where Pi2 pulsations have been observed in unexpected places. The new Pi2 models cover virtually all magnetotail regions and their coupling, from the reconnection site via the lobes and plasma sheet to the ionosphere.In addition to understanding the Pi2 phenomenon in itself, it has also been important to study Pi2 pulsations in their role as transient manifestations of the coupling between the magnetosphere and the ionosphere. The transient Pi2 is an integral part of the substorm phenomenon, especially during substorm onset. Key questions about the workings of magnetospheric substorms are still awaiting answers, and research on Pi2 pulsations can help with those answers. Furthermore, the role of Pi2 pulsations in association with other dynamic magnetospheric modes has been explored in the last decade. Thus, the application of Pi2 research has expanded over the years, assuring that Pi2 research will remain active in this decade and beyond.Here we review recent advances, which have given us a new understanding of Pi2 pulsations generated at various places in the magnetosphere during different magnetospheric modes. We review seven Pi2 models found in the literature and show how they are supported by observations from spacecraft and ground observatories as well as numerical simulations. The models have different degrees of maturity; while some enjoy wide acceptance, others are still speculative.

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Section: Modelmentioning

confidence: 97%

Review of Pi2 Models

2011

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“…Ultralow frequency (ULF) magnetic field fluctuations are one of the modes of energy and momentum transfer within the solar wind-magnetosphere-ionosphere (SW-M-I) system [e.g., Kivelson, 2013]. Coupling via ULF waves is typically the strongest at auroral and polar cap latitudes, which contributes to the complex behavior of the high-latitude ionosphere.…”

Section: Introductionmentioning

confidence: 99%

Large‐amplitude GPS TEC variations associated with Pc5–6 magnetic field variations observed on the ground and at geosynchronous orbit

et al. 2015

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Large‐amplitude variations in GPS total electron content (TEC) at Pc5–6 (<6.67 mHz) frequencies have been observed, using a high data rate Global Positioning System (GPS) receiver of the Canadian High Arctic Ionospheric Network. TEC variations with peak‐to‐peak amplitudes of 2–7 TEC units (1 TECU = 1016 el m−2) were observed over a 2.5 h period in the postnoon sector on 9 September 2011, during a period of high auroral activity within a moderate geomagnetic storm. TEC observations were from the Sanikiluaq, Nunavut (56.54°N, 280.77°E) GPS receiver located in the auroral region. Over this same time period, compressional Pc5–6 magnetic field variations were observed by the geosynchronous GOES 13 magnetometer and the ground‐based Sanikiluaq magnetometer. GOES 13 has a northern magnetic footprint in close proximity to Sanikiluaq. Cross‐correlation analysis indicates that magnetic field and TEC variations were possibly linked. No natural hazards or nuclear explosions capable of exciting TEC perturbations were reported on this day. Using a triangulation technique involving TEC measurements of multiple GPS satellites, the propagation velocity of TEC variations in the ionosphere was also calculated. This calculation revealed two distinct events: lower frequency (~0.9 mHz) TEC variations that propagated westward, consistent with the westward propagation of compressional Pc5 waves observed by GOES 13 and 15 satellites, and higher‐frequency (~3.3 mHz) TEC variations that propagated southward. This is the first report of variations in ionospheric TEC linked to satellite observations of Pc5–6 ULF waves.

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“…One of the difficulties of studying waves in the magnetosphere is that conditions change rapidly and thus standing waves are difficult to maintain (Kivelson, 2006). This translates into a strong damping of the waves and thus multi-point observations are necessary to study the different regions affected at the same time.…”

Section: Ulf Waves In the Magnetospherementioning

confidence: 99%

Investigation of a low-cost magneto-inductive magnetometer for space science applications

Regoli¹,

Moldwin²,

Pellioni³

et al. 2018

Geosci. Instrum. Method. Data Syst.

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Abstract.A new sensor for measuring low-amplitude magnetic fields that is ideal for small spacecraft is presented. The novel measurement principle enables the fabrication of a low-cost sensor with low power consumption and with measuring capabilities that are comparable to recent developments for CubeSat applications. The current magnetometer, a software-modified version of a commercial sensor, is capable of detecting fields with amplitudes as low as 8.7 nT at 40 Hz and 2.7 nT at 1 Hz, with a noise floor of 4 pT/ √ Hz at 1 Hz. The sensor has a linear response to less than 3 % over a range of ±100 000 nT. All of these features make the magneto-inductive principle a promising technology for the development of magnetic sensors for both space-borne and ground-based applications to study geomagnetic activity.

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ULF waves from the ionosphere to the outer planets

Cited by 21 publications

References 56 publications

Review of Pi2 Models

Review of Pi2 Models

Large‐amplitude GPS TEC variations associated with Pc5–6 magnetic field variations observed on the ground and at geosynchronous orbit

Investigation of a low-cost magneto-inductive magnetometer for space science applications

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