Imperial College London
Professor Quenby

Professor Quenby

Faculty of Natural Sciences, Department of Physics

Distinguished Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 7527j.quenby

 
 
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Location

 

1106Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Quenby:2015:mnras/stv1482,
author = {Quenby, JJ and Webber, WR},
doi = {mnras/stv1482},
journal = {Monthly Notices of the Royal Astronomical Society},
pages = {1297--1304},
title = {Transient heliosheath modulation},
url = {http://dx.doi.org/10.1093/mnras/stv1482},
volume = {453},
year = {2015}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Voyager 1 has explored the solar wind–interstellar medium interaction region between the terminal shock and heliopause, following the intensity distribution of Galactic cosmic ray protons above 200 MeV energy. Before this component reached the expected galactic flux level at 121.7 au from the Sun, four episodes of rapid intensity change occurred with a behaviour similar to that found in Forbush Decreases in the inner Solar system, rather than that expected from a mechanism related to models for the long-term modulation found closer to the Sun. Because the mean solar wind flow is both expected and observed to be perpendicular to the radial direction close to the heliopause, an explanation is suggested in terms of transient radial flows related to possible heliopause boundary flapping. It is necessary that the radial flows are of the order either of the sound speed found for conditions downstream of the terminal shock or of the fluctuations found near the boundary by the Voyager 1 Low Energy Charged Particle detector and that the relevant cosmic ray diffusion perpendicular to the mean field is controlled by ‘slab’ fluctuations accounting for about 20 per cent of the total power in the field variance. However, additional radial drift motion related to possible north to south gradients in the magnetic field may allow the inclusion of some diffusion according to the predictions of a theory based upon the presence of 2D turbulence. The required field gradients may arise due to field variation in the field carried by solar plasma flow deflected away from the solar equatorial plane. Modulation amounting to a total 30 per cent drop in galactic intensity requires explanation by a combination of transient effects.
AU  - Quenby,JJ
AU  - Webber,WR
DO  - mnras/stv1482
EP  - 1304
PY  - 2015///
SN  - 1365-2966
SP  - 1297
TI  - Transient heliosheath modulation
T2  - Monthly Notices of the Royal Astronomical Society
UR  - http://dx.doi.org/10.1093/mnras/stv1482
UR  - http://hdl.handle.net/10044/1/27835
VL  - 453
ER  -
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