First incoherent scatter radar observations of ionospheric heating on the second electron gyro-harmonic

Kosch, M. J.; Gustavsson, B.; Heinselman, C. J.; Pedersen, T. R.; Rietveld, M. T.; Spaleta, J.; Wong, A. Y.; Wang, W.; Mutiso, C. K.; Bristow, B.; Hughes, John M.

doi:10.1016/j.jastp.2009.08.007

Cited by 5 publications

(5 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure compares representative ion‐line power spectra associated with natural turbulence (Figure a) and heater‐induced turbulence (Figure b), both observed with PFISR. The heater‐induced turbulence was generated by the High Power Auroral Stimulation heater, which was located ~35 km from PFISR [ Kosch et al ., ]. In each case, the spectra were calculated using a 72 km long pulse.…”

Section: Observationsmentioning

confidence: 99%

Localization of auroral Langmuir turbulence in thin layers

et al. 2013

View full text Add to dashboard Cite

[1] The recently discovered coherent echoes in the Poker Flat Incoherent Scatter Radar data with flat ion-line spectrum and simultaneous double-peaked plasma-line spectrum in the lower ionospheric F region are investigated in greater detail. High-range resolution measurements reveal that the turbulence is sometimes manifested as two concurrent layers separated by about 50 km. The turbulence layers appear at regions of zero electron density gradient, supporting the interpretation that propagation effects play an important role in limiting the waves' amplitude. Although Langmuir intensity is limited by propagation effects outside of the layers, it reaches to nonlinear regime inside the layers, giving rise to the observed range and spectral morphologies. Furthermore, the radar measurements of the electrostatic waves appear to be correlated in space and time with natural auroral electromagnetic emissions, supporting the previous theory that "MF-bursts" are produced by linear conversion of Langmuir waves produced by soft electron precipitation (~few hundred electronvolts) on the topside F region. The results presented in this report suggest that the observed Langmuir turbulence and MF-burst are both manifestations of the same process.

show abstract

Section: Observationsmentioning

confidence: 99%

Localization of auroral Langmuir turbulence in thin layers

et al. 2013

View full text Add to dashboard Cite

show abstract

“…This suggests that at high latitudes, the excitation of UH waves and FAI are the major source of electron heating, though other mechanisms are not excluded. The behavior around the second gyroharmonic is an exception: Kosch et al [2009] found that electron heating maximized around the second gyroharmonic.…”

Section: Introductionmentioning

confidence: 99%

The dependence of F‐region electron heating on HF radio pump power: Measurements at EISCAT Tromsø

et al. 2012

View full text Add to dashboard Cite

[1] Measurements of ionospheric electron temperature enhanced by the action of a powerful high-frequency radio wave on the F-region at the EISCAT facility near Tromsø, Norway are analyzed to obtain the electron heat source due to the radio wave as a function of transmitter power. The absorption of the wave in the D-region is accounted for and is found to have a significant influence on the F-region heating, especially due to variations in the D-region electron density during the experiment. It is found that the efficiency of F-region heating expressed in terms of the electron heating rate as a function of radio wave power flux is higher at higher transmitter powers. This behavior seems to be consistent with the development of geomagnetic field-aligned plasma density irregularities which are associated with the conversion of the radio wave to electrostatic upper-hybrid waves. At the highest power fluxes, the efficiency appears to be close to 100%.

show abstract

“…Electron acceleration and heating is a fundamental process in space physics. It is observed in the F-region ionosphere (Lund et al, 2012;Schunk & Nagy, 1978), in auroral cavity regions (Menietti et al, 1994;Morgan et al, 2000), in active ionosphere modification experiments (Kosch et al, 2009;Robinson et al, 1996), in solar wind turbulence (Sahraoui et al, 2009), in magnetosphere reconnection (Phan et al, 2013), and in the bow shock (Chen et al, 2018). Many radar and satellite measurements show that ionospheric thermal electrons (of the order 0.1 eV) are often heated up to several eV near the F-region ionosphere (Curtis et al, 1985;Lund et al, 2012;Schunk & Nagy, 1978;Seo et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Suprathermal Electron Acceleration Perpendicular to the Magnetic Field in the Topside Ionosphere

Shen

Knudsen

2020

JGR Space Physics

View full text Add to dashboard Cite

We present the first direct observations of suprathermal (tens to hundreds of eV) electron acceleration perpendicular to the magnetic field in the topside (900–1,500 km) ionosphere. Based on measurements from the suprathermal electron imager (SEI) onboard the Enhanced Polar Outflow Probe satellite over several months, we identify 30 events (28 in the dayside cusp) of enhanced suprathermal electron fluxes peaking at ±90° pitch angles, with energies spanning from tens of eV to 325 eV, the upper limit of the SEI measurement. These events take place with a time duration of the order of 0.1 s, corresponding to a spatial scale of less than 1 km across the magnetic field. They are associated with parallel suprathermal electron bursts and upward currents. The correlation between perpendicular and parallel suprathermal electrons suggests a scenario in which downward bursts and the associated Alfvén waves that drive them provide a free energy source to destabilize plasma waves at electron frequencies, which in turn heat electrons in the perpendicular direction. This is a new energy dissipation process for cusp suprathermal electron precipitation in the topside ionosphere.

show abstract

First incoherent scatter radar observations of ionospheric heating on the second electron gyro-harmonic

Cited by 5 publications

References 32 publications

Localization of auroral Langmuir turbulence in thin layers

Localization of auroral Langmuir turbulence in thin layers

The dependence of F‐region electron heating on HF radio pump power: Measurements at EISCAT Tromsø

Suprathermal Electron Acceleration Perpendicular to the Magnetic Field in the Topside Ionosphere

Contact Info

Product

Resources

About