Equator‐S observations of ion cyclotron waves outside the dawnside magnetopause

Dunlop, M. W.; Lucek, E.; Kistler, L. M.; Cargill, P. J.; Balogh, A.; Baumjohann, W.

doi:10.1029/2001ja900170

Cited by 9 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Observationally, the most extensively used method for selecting star-forming galaxies at high redshifts is the Lyman drop-out technique (for details on other methods see the review by Dunlop 2012). This technique uses near-UV, optical and near-IR filters (depending on the target redshift) to sample the redshifted Lyman-break, thereby selecting star-forming galaxies, the so called Lyman Break Galaxies (LBGs).…”

Section: Lyman-break Selection For Galaxies At High Redshiftsmentioning

confidence: 99%

The ultraviolet colours and dust attenuation of Lyman-break galaxies

González-Pérez

Lacey

Baugh

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Using galform, a semi-analytical model of galaxy formation in the Λ cold dark matter cosmology, we study the rest-frame ultraviolet (UV) colours of Lyman-break galaxies (LBGs) in the redshift range 2.5 ≤ z ≤ 10. As the impact of dust on UV luminosity can be dramatic, our model includes a self-consistent computation of dust attenuation based on a radiative transfer model. We find that intrinsically brighter galaxies suffer stronger dust attenuation than fainter ones, though the relation has a large scatter. The model predicts galaxies with UV colours consistent with the colour selection regions designed to select LBGs in observational surveys. We find that the drop-out technique that selects LBGs based on two rest-frame UV colours is robust and effective, selecting more than 70 per cent of UV bright galaxies at a given redshift. We investigate the impact on the predicted UV colours of varying selected model parameters. We find that the UV colours are most sensitive to the modelling of dust attenuation and, in particular, to the extinction curve used in the radiative transfer calculation. If we assume a Milky Way dust extinction curve, the predicted UV continuum slopes are, in general, bluer than observed. However, we find that the opposite is true when using the Small Magellanic Cloud dust extinction curve. This demonstrates the strong dependence of UV colours on dust properties and highlights the inadequacy of using the UV continuum slope as a tracer of dust attenuation without any further knowledge of the galaxy inclination or dust characteristics in high redshift galaxies.

show abstract

Section: Lyman-break Selection For Galaxies At High Redshiftsmentioning

confidence: 99%

The ultraviolet colours and dust attenuation of Lyman-break galaxies

González-Pérez

Lacey

Baugh

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…There are very few or no angular changes across the mirror-mode magnetic field structures, and the total (magnetic+ plasma) pressure remains constant throughout. These are well studied theoretically (Chandrasekhar et al 1958;Vedenov & Sagdeev 1958;Hasegawa 1969Hasegawa , 1975Price et al 1986;Pokhotelov et al 2008;Hasegawa & Tsurutani 2011) and from an observational point of view (Tsurutani et al 1982;Treumann et al 1990Treumann et al , 2000Lacombe et al 1992;Chisham et al 1998Chisham et al , 1999Lucek et al 1999aLucek et al , 1999bLucek et al , 2001Dunlop et al 2002;Tátrallyay & Erdös 2002Constantinescu et al 2003Constantinescu et al , 2006Horbury et al 2004;Narita & Glassmeier 2005;Narita et al 2006;Soucek et al 2008; Horbury & Lucek 2009;Tsurutani et al 2011b). These structures arise due to an ion temperature anisotropy with T ⊥i > T i , a condition that also excites the ion cyclotron instability (Kennel & Petschek 1966;Sckopke et al 1990;Lacombe et al 1992;Tsurutani et al 2002aTsurutani et al , 2002b.…”

Section: Introductionmentioning

confidence: 97%

Large-Amplitude, Circularly Polarized, Compressive, Obliquely Propagating Electromagnetic Proton Cyclotron Waves Throughout the Earth's Magnetosheath: Low Plasma Β Conditions

Remya

Tsurutani

Reddy

et al. 2014

ApJ

View full text Add to dashboard Cite

During 1999 August 18, both Cassini and WIND were in the Earth's magnetosheath and detected transverse electromagnetic waves instead of the more typical mirror-mode emissions. The Cassini wave amplitudes were as large as ∼14 nT (peak to peak) in a ∼55 nT ambient magnetic field B 0. A new method of analysis is applied to study these waves. The general wave characteristics found were as follows. They were left-hand polarized and had frequencies in the spacecraft frame (f scf) below the proton cyclotron frequency (f p). Waves that were either right-hand polarized or had f scf > f p are shown to be consistent with Doppler-shifted left-hand waves with frequencies in the plasma frame f pf < f p. Thus, almost all waves studied are consistent with their being electromagnetic proton cyclotron waves. Most of the waves (∼55%) were found to be propagating along B 0 (θ kB 0 < 30 •), as expected from theory. However, a significant fraction of the waves were found to be propagating oblique to B 0. These waves were also circularly polarized. This feature and the compressive ([B max − B min ]/B max , where B max and B min are the maximum and minimum field magnitudes) nature (ranging from 0.27 to 1.0) of the waves are noted but not well understood at this time. The proton cyclotron waves were shown to be quasi-coherent, theoretically allowing for rapid pitch-angle transport of resonant protons. Because Cassini traversed the entire subsolar magnetosheath and WIND was in the dusk-side flank of the magnetosheath, it is surmised that the entire region was filled with these waves. In agreement with past theory, it was the exceptionally low plasma β (0.35) that led to the dominance of the proton cyclotron wave generation during this interval. A high-speed solar wind stream (V sw = 598 km s −1) was the source of this low-β plasma.

show abstract

“…Low-frequency electromagnetic cyclotron waves (i.e., ion cyclotron waves) are usually observed in different solarterrestrial environments, i.e., the Earth's magnetosphere, the magnetosheath, and the solar wind (e.g., Anderson & Fuselier 1993Dunlop et al 2002;Jian et al 2014;Remya et al 2014;Wicks et al 2016;Zhao et al 2018). These waves play an important role in the dynamics of charged particles.…”

Section: Introductionmentioning

confidence: 99%

Modulation of Ion and Electron Pitch Angle in the Presence of Large-amplitude, Low-frequency, Left-hand Circularly Polarized Electromagnetic Waves Observed by MMS

Zhao

Wang²,

Dunlop

et al. 2018

ApJ

Self Cite

View full text Add to dashboard Cite

Most studies on low-frequency electromagnetic cyclotron waves have assumed a small wave amplitude, which ensures the reasonable application of linear and quasi-linear theories. However, the topic of large-amplitude electromagnetic cyclotron waves has not received much attention. Using Magnetospheric Multiscale measurements, this study observes low-frequency, left-hand circularly polarized electromagnetic waves with magnetic fluctuation ∼1-2 nT in the dusk flank side of the Earth's magnetosheath. Considering the ambient magnetic field ∼15 nT therein, the relative wave amplitude is of the order of 0.1. These large magnetic field fluctuations result in a periodic variation of the ion pitch angle. The electron pitch angle exhibits a localized distribution feature with a timescale approximating the wave period. Moreover, some electrons are trapped at a pitch angle ∼90°, and the trapping is more remarkable as strong waves arise. These two features of the electron pitch angle distribution imply that the trapping of electrons (partly) results from large-amplitude electromagnetic cyclotron fluctuations. Our results illustrate the important role of large-amplitude electromagnetic cyclotron waves on the dynamics of charged particles.

show abstract

Equator‐S observations of ion cyclotron waves outside the dawnside magnetopause

Cited by 9 publications

References 25 publications

The ultraviolet colours and dust attenuation of Lyman-break galaxies

The ultraviolet colours and dust attenuation of Lyman-break galaxies

Large-Amplitude, Circularly Polarized, Compressive, Obliquely Propagating Electromagnetic Proton Cyclotron Waves Throughout the Earth's Magnetosheath: Low Plasma Β Conditions

Modulation of Ion and Electron Pitch Angle in the Presence of Large-amplitude, Low-frequency, Left-hand Circularly Polarized Electromagnetic Waves Observed by MMS

Contact Info

Product

Resources

About