Effects of particle drifts on the solar modulation of galactic cosmic rays

Jokipii, J. R.; Levy, E. H.

doi:10.1086/182415

Cited by 100 publications

(51 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the presence of the HCS, the latitudinal drifts in each hemisphere play a significant role to how protons propagate (see, e.g., Jokipii & Levy 1977). For protons injected at and near the HCS, as in our simulations, we find the dynamics presented to differ significantly from the unipolar case.…”

Section: Resultssupporting

confidence: 56%

Solar Energetic Particle Transport Near a Heliospheric Current Sheet

Battarbee

Dalla

Marsh

2017

ApJ

View full text Add to dashboard Cite

Solar energetic particles (SEPs), a major component of space weather, propagate through the interplanetary medium strongly guided by the interplanetary magnetic field (IMF). In this work, we analyze the implications that a flat Heliospheric Current Sheet (HCS) has on proton propagation from SEP release sites to the Earth. We simulate proton propagation by integrating fully 3D trajectories near an analytically defined flat current sheet, collecting comprehensive statistics into histograms, fluence maps, and virtual observer time profiles within an energy range of 1-800 MeV. We show that protons experience significant current sheet drift to distant longitudes, causing time profiles to exhibit multiple components, which are a potential source of confusing interpretations of observations. We find that variation of the current sheet thickness within a realistic parameter range has little effect on particle propagation. We show that the IMF configuration strongly affects the deceleration of protons. We show that in our model, the presence of a flat equatorial HCS in the inner heliosphere limits the crossing of protons into the opposite hemisphere.

show abstract

Section: Resultssupporting

confidence: 56%

Solar Energetic Particle Transport Near a Heliospheric Current Sheet

Battarbee

Dalla

Marsh

2017

ApJ

View full text Add to dashboard Cite

show abstract

“…The brevity of the spike and the lack of explicit relationship to tilt angle may mean that it requircs some modification of the simplest interpretation of thc alternating flat and peaked solar cycles [Jokipii and Levy, 1977]. Thc spike can possibly be understood in gcncral terms by observing that the particles that drift away from the current sheet havc much larger radial gradients than those that drift toward it.…”

Section: Discussionmentioning

confidence: 99%

Charge sign dependence of cosmic ray modulation near a rigidity of 1 GV

Clem¹,

Evenson²,

Huber³

et al. 2000

J. Geophys. Res.

View full text Add to dashboard Cite

“…Another is the effect of mixed polarity field on the transport of charged particles. As shown by Jokipii & Levy (1977), drift along the HCS is important for modulation of galactic cosmic rays; the effects of a wavy HCS were also considered (Miyake et al 2005;Usoskin et al 2008) Penetration of small charged grains into the heliosphere is facilitated by effective reduction of the magnetic field in the mixed polarity regions (Landgraf 2000;Czechowski & Mann 2003). Also, the distribution of energetic (>28 keV) particles in the heliosheath, which can now be studied in detail thanks to Voyager observations (Decker et al 2005(Decker et al , 2008Stone et al 2005Stone et al , 2008, is likely to be affected by the drift along the folded current sheet extending to high latitudes.…”

Section: Introductionmentioning

confidence: 84%

Structure of the heliospheric current sheet from plasma convection in time-dependent heliospheric models

Czechowski¹,

Strumik²,

Grygorczuk³

et al. 2010

A&A

View full text Add to dashboard Cite

Context. The heliospheric current sheet is a plasma layer dividing the heliosphere into the regions of different magnetic field polarity. Since it is very thin compared to the size of the system, it is difficult to incorporate into the numerical models of the heliosphere. Because of the solar magnetic field reversals and the diverging and slowing down plasma flow in the outer heliosphere, the heliospheric current sheet is expected to have a complicated structure, with important consequences for transport processes in the heliosheath. Aims. We determine the shape and time evolution of the current sheet in selected time-dependent 3-D models of the heliosphere, assuming that the heliospheric current sheet is a tangential discontinuity convected by the plasma flow. Methods. We have derived the shape of the heliospheric current sheet at a given time by following the plasma flow lines originating at the neutral line on the source surface surrounding the Sun. The plasma flow was obtained from numerical MHD or gas-dynamical solutions.Results. The large-scale structure of the magnetic field polarity regions and the heliospheric current sheet in time-dependent asymmetric models of the heliosphere differs from the results obtained in simpler models. In particular, in the forward heliosheath it is characterized by secondary folds in the heliospheric current sheet that are caused by the solar wind latitudinal variation over the solar cycle. We present examples illustrating some cases of interest: a "bent" current sheet, and the HCS structure during the magnetic field reversal at the solar maximum. We also discuss the evolution of the magnetic polarity structure in the region close to the heliopause.

show abstract

Effects of particle drifts on the solar modulation of galactic cosmic rays

Cited by 100 publications

References 0 publications

Solar Energetic Particle Transport Near a Heliospheric Current Sheet

Solar Energetic Particle Transport Near a Heliospheric Current Sheet

Charge sign dependence of cosmic ray modulation near a rigidity of 1 GV

Structure of the heliospheric current sheet from plasma convection in time-dependent heliospheric models

Contact Info

Product

Resources

About