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N. A. Frissell (Space@VT) GEM Student Day 16 June 2013

Nathaniel Frissell

Virginia Tech SuperDARN Laboratory 2011-‐2013 GEM Student RepresentaBve


Intro to Inner Magnetosphere

•  Interested in the response and coupling of the inner magnetosphere and ionosphere during storms

Sudden Commencement

Main Phase

Recovery Phase

Day 134 136 142 144 Dst

-100

0

50

-150

[h8p://pluto.space.swri.edu/image/glossary/magnetosphere2.html]


ConvecIon Review


•  Magnetospheric convecBon can be seen down into the ionosphere.

•  Under normal condiBons, convecBon is not seen below the auroral zone.

ConvecIon Review

©The COMET Program


SIMIC Focus Group

•  Long standing interest in this topic by the GEM Community: –  (h8p://www-‐ssc.igpp.ucla.edu/gemwiki/index.php/GEM_Tutorials)

–  2011: Inner Magnetosphere-‐Ionosphere (IMI) Coupling (MI Coupling -‐ IM Coupling) by Pontus Brandt (APL/JHU) and Mark Moldwin (University of Michigan)

•  Nice video and really good at showing the GEM-‐CEDAR connecBon. They emphasize that we need to look at the whole system in order to solve the problem.

–  2005: Sub-‐AuroralElectric Fields:An Inner Magnetosphere PerspecBve by Bob Spiro

–  2002: Inner Magnetospheric Electric Fields by Rich Wolf


SIMIC Focus Group

1.  They control plasmasphere and ring-‐current dynamics. We won’t understand ring current injecBon unBl we understand the associated electric fields.

2.  They affect the radiaBon belts somewhat (through inducBon electric fields, and waves are probably more important).

3.  They drive much of the dynamics of the low-‐ and mid-‐laBtude ionosphere

4.  They seem to be the most unknown element in modern ionospheric modeling of the subauroral ionosphere.

5.  DisrupBons of the mid-‐ and low-‐laBtude ionosphere seem to be the most important aspects of space weather at present, parBcularly for the military.

[Wolf, 2002, GEM Tutorial]


•  Inner Magnetospheric Models –  RAM-‐SCM –  HEIDI –  CRCM –  Rice ConvecBon Model (RCM and RCM-‐E)

•  Ground-‐Based Subauroral Ionosphere –  MidlaBtude SuperDARN –  GPS-‐TEC –  Incoherent Sca8er Radar (ISRs) –  THEMIS GBO

•  In-‐situ Inner Magnetosphere and Ionosphere –  Van Allen Probes –  THEMIS –  Cluster –  AMPERE –  DMSP –  POES

New InstrumentaIon


New InstrumentaIon


New InstrumentaIon

[B. Kunduri]


•  PenetraIon Electric Fields •  SAPS: Sub-‐auroral polarizaIon stream


•  ApplicaBon of Cross-‐Tail E Moves Plasmasheet Sunward

•  Causes a parBal westward ring across night side

•  Dusk side of edge charges +, dawn side -‐. •  Charging occurs near eq. plane and in

ionosphere •  Region 2 Currents flow down into the

ionosphere at dusk and up from on the dawnside.

•  These Region 2 Currents tend to shield the near-‐Earth region from the dawn-‐dusk E. Dusk-‐dawn polarizaBon E opposes convecBon in the inner magnetosphere.

Plasma sheet

E=0

Gradient/curvature drift currents

+

<

E

Eshielding

ConvecIon Electric Field

[Wolf, 2002, GEM Tutorial]


E(reduced)

E(overshielding)

E (Reduced) E (Increased)

•  Undershielding – Southward IMF leads to convecBon increase

– Results in dawn-‐dusk E in Inner Mag •  Overshielding

– Sudden Northward IMF Turning – Results in dusk-‐dawn E in Inner Mag – First seen at Jicamarca by Kelley et al. (GRL, 6, 301, 1977)

OVERSHIELDING


[RCM Runs by Stan Sazykin, Figures from F. Toffoletto CISM Tutorial]


[L. Clausen]

IMF Bz [n

T]

Ft. H

ays, Kan

sas

Supe

rDAR

N

N-‐S Velocity

[m/s]


[L. Clausen]


•  SAPS (subauroral polarizaBon stream) is defined as a relaBvely narrow channel (~5˚ MLAT) of westward flow, located just below the lower auroral electron precipitaBon boundary on the nightside.

•  SAID (subauroral ion drim) is defined as a narrower, faster channel someBmes observed in the SAPS.

[Clausen et al., 2012]

9 April 2011

N. A. Frissell (Space@VT) GEM Student Day 16 June 2013 [Clausen et al., 2012]


•  Inner magnetosphere-‐ionospheric coupling has been studied for many years, but… – TradiBonally, instrumentaBon has been sparse. – Modelers need more observaBons to develop, constrain, and validate the models.

•  Today, – We now have much be8er inner magnetosphere-‐ionospheric instrumental coverage.

– Models are poised to take the next step.


Storm-‐Time Inner Magnetosphere – Ionosphere ConvecIon

MoIvaIon 1.  ConBnue the improvement and validaBon of physics-‐based models of the

coupled inner magnetosphere. 2.  Many recent expansions of both ground-‐ and space-‐ based instrumentaBon,

especially at midlaBtudes and the inner magnetospheric region. 3.  Recent ramping up of solar acBvity leading to increased geomagneBc acBvity.

Vision This FG will bring together experimentalists, modelers, and theorists to synthesize a new understanding of how plasma distribuBons, convecBon electric fields, and current systems emerge and evolve in the inner magnetosphere and conjugate ionosphere during geomagneBc storms.


1.  Develop an improved canonical descripBon of convecBon in the coupled inner magnetosphere -‐ ionosphere during storms

2.  Validate and improve the performance of coupled inner magnetosphere-‐ionosphere models

3.  Make steps toward developing a new module for acBve ionospheric feedback during storms.

Read the full proposal here: h8p://www-‐ssc.igpp.ucla.edu/gemwiki/index.php/FG:_Storm-‐

Time_Inner_Magnetosphere-‐Ionosphere_ConvecBon


Joseph Baker Virginia Tech

J. Michael Ruohoniemi Virginia Tech

Stanislav Sazykin Rice University

Peter Chi University of California Los Angeles

Mark Engebretson Augsburg College


•  Download this and all other student tutorials at the GEMwiki Student Forum: h8p://www-‐ssc.igpp.ucla.edu/gemwiki

[email protected]


(h8p://www-‐ssc.igpp.ucla.edu/gemwiki/index.php/GEM_Tutorials)

– 2011: Inner Magnetosphere-‐Ionosphere (IMI) Coupling (MI Coupling -‐ IM Coupling) by Pontus Brandt (APL/JHU) and Mark Moldwin (University of Michigan)

•  Nice video and really good at showing the GEM-‐CEDAR connecBon. They emphasize that we need to look at the whole system in order to solve the problem.

– 2005: Sub-‐AuroralElectric Fields:An Inner Magnetosphere PerspecBve by Bob Spiro

– 2002: Inner Magnetospheric Electric Fields by Rich Wolf


Clausen, L. B. N., et al. (2012), Large-‐scale observaBons of a subauroral polarizaBon stream by midlaBtude SuperDARN radars: Instantaneous longitudinal velocity variaBons, J. Geophys. Res., 117, A05306, doi:10.1029/2011JA017232.

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