Electrodynamics coupling between High and Low latitudes

Christine Amory-Mazaudier

LPP/UPMC/Polytechnique/CNRS

Christine.amory@lpp.polytechnique.fr

Outline

• Dynamo Mechanisms

• Some historical steps -1961 until now• Prompt penetration of magnetospheric convection

• Storm winds and Ionospheric disturbance dynamo

• Some studies in Africa

• Conclusions

N B: Changes in composition are not presented

Principle of the DYNAMO ACTION

MOTIONMAGNETIC FIELD

OHM’S LAW

j = s (E + VxB)

AMPERE’S LAW

xB = mj

LORENTZ ‘S FORCE

jxB

V B

E

jB

VxB

Starting point

FARADAY’S LAW

xE= -dB/dt

Polarisation Electric field

Dynamo Electric field

4

Dynamo Motions – V Magnetic field B Order of Magnitude

Sun SunRotation and convection

Sun : 2 componentsDipolarToroïdal = sunspot

rotation speed : ~ 7280km/hat the equatorDipolar component : ~10 GToroidal component : ~3-5 kG

Solar wind Magnetosphere

Solar wind Interplanetary medium-> Bi

speed ~ [ 400km/s to 1000km/s]Bi ~ qq 10 nT

Atmospheric windIonosphere

Atmosphere Earth’s -> Bt

speed ~ 100m/sBt ~ qq 10 000 nT

Earth’s Dynamoinside the Earth

Metallic core Earth’s -> Bt

Indirect measurements deduced from the Earth’s planetary magnetic field and the secular variation Velocity ~ qq km/yearBt ~ qq 10 000 nT

Geophysical studies : the initial workall the data are available on the web

Sun

– Sunspot cycle, poloidal cycle

– Solar event

• Solar wind parameters V,B

– Solar wind magnetosphere dynamo

• Dst -> [Hsym and H asym]

– Ring current

• AU and AL

– Auroral electrojets

• Ionospheric parameters

• Earth’s magnetic field

NECESSITY TO ANALYZE MANY PARAMETERS in order tounderstand the magnetic field, TEC etc… observations

Solar wind / magnetosphere Dynamo

Bz southward

Key parameters : Solar wind speed and Interplanetary Magnetic field Bz component

7

LDynamo solar wind /magnetosphere / Theory and ObservationsSolar wind + interplanetary magnetic field

Viscous interaction between the solar wind and the magnetosphere Axford and Hines, 1961The interplanetary magnetic field is transmitted to the magnetosphereE = -Vsx Bi => Ey = -VxBz

Reconnexion Dungey 1961Connexion between the interplanetary and the earth magnetic fields

This process is based on a closed magnetosphere

These 2 processes lead to motion of the particules inside the magnetosphere

Magnetic storm and associated phenomena K.D. Cole, 1966, Space Science review (5), 699-770

D = DCF + DR + DT + DI + DG

Cross-Tail Current Sheet

J//-Region1

J//-Region2

MAGNETOSPHERIC ELECTRIC CURRENTS

associated to the solar wind magnetosphere dynamo

9

J//-

Region2

Currents on the MAGNETOPAUSE

Ring current

Dawn-dusk voltage drop difference to the magnetosphere

Particles follow trajectories from the tail of the magnetosphere toward the Earth

In the region where the curvature and gradient of the Earth’s ‘s

magnetic field are strong,

particles are separated, the electrons are diverted to the morning side and the ions

to the evening side.

Formation of the ring currentCharge Space Shielding effect

Akasofu, 1981

11

Auroral electrojets

Middle latitudes currents

Equatorial Electrojet

Field aligned current

Auroral electrojets

Precipitation of particles

Electric field

Ionospheric electric currents DI

associated to the Solar wind magnetosphere dynamo

At low latitudes => DI = DP2 +Ddyn (2005)Ionospheric current disturbance with large extension [there are other currents confined on the polar cap as DP0 , DP1, DP3 and DP4]

• ELECTRIC FIELD ALONE

• Prompt penetration of the magnetospheric convection electric field [ PPE]

+ DEc DJ DBmagnetospheric convection electric field

Figure from Nishida 1968

PPE

The electric field Ec is transmitted to

the whole ionosphere

=> simultaneity of the disturbances

from auroral to equatorial latitudes

Penetration of the magnetospheric convection electric field to the

equator , Kikuchi et al., 2000, JGR, Vol 105, N° A10, 23251-23261

Direct process

DDP

No shielding

Loaded drivenprocess/RC

ShieldingorOvershielding

PPE

EQUIVALENT CURRENT SYSTEMS

Sqp Nagata and Kokubun, 1962

Rep. Ionoph Space Japan, 16, 150This current system is confined at High latitudes (magnetic quiet time)

now DP0

DP2, Nishida, 1968, JGR, 73, 5549

This current system extends towardLow latitudes (magnetic disturbed time)[Nishida et al., 1966]

PPE

Electric current : a preliminary study of disturbances

Mazaudier, JGR 1985, 90, (A2), 1355-1366

PPE

No shielding : weak activity on the daysideMazaudier, JGR, 1985, 90, (A2), 1355-1366

Saint-Santin Incoherent sounder

DH~JY ~ - SHEXDrift ~ 25m/s => Electric field ~ 1mV/m

PPE

Vper =(ExB)/B2

Electrodynamic coupling of high and low latitudes observations on May, 27, 1993

Kobéa et al. 2000, JGR, Vol 105, A10, 22979-22989

Richmond and Kamide, 1988 AMIEJGR vol 83 n°A6, 5741-5759

PPE

Overshieldingrelated to R2 FacPeymirat et al.,

JGR 2000TIEGCM

Direct Penetration of the polar electric field to the equator during a DP2 event as detected by the auroral and equatorial magnetometer

chains and the ESICAT radar, Kikuchi et al. , JGR 1996

PPE

Long duration penetration of the

interplanetary electric field to the low-latitude during the main phase of magnetic storm

Huang et al., JGR, Vol 1110, A11309, 2005

PPE

Penetration electric fields : Efficiency andCharacteristics time scale,

Huang et al.,JASTP, 69 2007, 1135

9,6%

First mathematical convection modelMathematical Models of Magnetospheric Convection and its coupling to

the ionosphere Vasyliunas, 1970, Mc Cormac book

Outlines of the self consitent calculation : calcultated quantities are in boxes, Lines joining boxes are labeled with the physical principle

Equipotential contours in the ionosphere (enhanced auroral conductivies)

PPE

Motion and

distibution

of particules

On the control of the magnetosphericconvection by the spatial distribution of Ionospheric conductivities

Senior and Blanc, 1984, Vol 89, N° A1, 261-284

Constant of shielding ~ 30’

OTHER MODELS

PPE

RICE CONVECTION MODEL(Toffoletto et al. 2003)most used today

This chart elaborates the basicscheme proposed by Vasyliunas

+ additional Model inputs (ovals)Outputs (rectangles)

Model and Data

Radar Studies of midlatitudes Ionospheric plasma drift

Schierless et al., 2001JGR, Vol 106, A2, 1771-1783

PPE

Short dashed line -> i nitial responseLong dashed line -> 10’ later

Sastri J., JGR 2002Vol 107, N° A12, 1448Penetration of elctric field at the nighsideDip equator associated with the mainImpulse of the SSC of 8 July, 1991

Storm winds and ionospheric disturbance dynamo=> delay between the auroral and equatorial zones

Auroral electrojets

Joule heating most effective

+ DVn DEdyn DJ DBGravity waves, HADLEY convection cell etc…

24/08/2005

Sreeja et al., JGR vol 114, A12307, 2009

SSC : 13.00 ISTMain Phase : 16 00 IST

INDIA77-78°E meridian

V~750m/s

Travelling Atmospheric Disturbance (TAD’s)

A time delay in the VTEC variations over the different latitudes indicates a

propagation of TAD’s Velocity 750m/s

Hayashi et al., 2010, JGR, vol 115, A06309

Large scale traveling ionospheric disturbance observed by superDARN, Hokkaido HF Radar and GPS networks on 15 December 2006

Possible origin in the southern hemisphere

600-650ms-1

Quiet magnetic variations

Regular electric current

J = s (E + Vn xB) -> Sq

Joule heating in auroral zone

Storm wind

DVn

In equatorial zone

DJ = s (DE + DVn xB)

Reversed equatorial electrojet Ddyn

HADLEY CELL BETWEEN POLE AND EQUATOR

Robble 1977

The Ionospheric Disturbance Dynamo

JGR,85, 1669-1686, 1980 Blanc and Richmond

Mazaudier and Venkateswaran, 1990Annales Geophysicae, 8, (7-8), 511-518

Richmond and Matshushita, JGR, 1975 vol 80, N°19, 2839-2850

Thermospheric response to a magnetic storm

Regular wind

Storm wind

1

2

3

4

5

6

DD

Saint-Santin Radar observations of lower thermospheric storms

Mazaudier et al., 1985JGR (90) A3, 2885-2895

DD

Dynamics of the F region observed with Thomson scatter 1. Atmospheric circulation and neutral wind

Vasseur, JATP, 31, 397, 1969

STORM WINDS

Saint-Santin Radar observations of lower thermospheric storms Mazaudier et al., 1985, JGR (90) A3, 2885-2895

DD

Average Daytime F region disturbance neutral winds measured by UARS : Initial results, Fejer et al., GRL, Vol 27, N°13, 1859-1862 ~ 2000?

Equatorial electric field ofIonospheric disturbance Dynamo originSastri Annales 1988, 6, (6), 635-642

DD

Abdu et al., 1997Longitudinal structure and spread F, A case study from GUARA/EITS campaignsGeophys. Res.lett., 24, 1707-1710

Difference H Field between Trivandrum

and Alibag -> equatorial electrojet strenght

Deviation from the average quiet day of

the month

sunrisesunset

Ahmedabad

crest

Kodaikanal

trough

Tomsk

No auroral activity after a storm

Criteria to select days to analyse

the ionospheric disturbance

dynamo

Ionospheric disturbance dynamo

AU

AL

Dst

Bz

Vx

DH= SR-DR + DP2 +Ddyn

DP2 = 0=> Ddyn = DH= SR-DR

Magnetic signature of the ionospheric disturbance dynamo at equatorial latitudes : Ddyn

Le Huy and Amory-Mazaudier, JGR, 2005 DD

12LT

12LT

12LT

Blanc and Richmond, 1980

Ddyn = DH-SR-DR

Magnetic signature of the Ionospheric disturbance dynamoLe Huy and Amory-Mazaudier, 2005

0 3 6 9 12 15 18 21 24

UT - November 24, 2001

-200

0

200

D

(nT)

- Bacl

ieu

3 6 9 12 15 18 21 24

UT - November 25, 2001

12 12

-200

0

200

D

(nT)

- Addis

Ababa

12 12

-200

0

200

D

(nT)

- H

uanca

yo

12 12

Figure 9.

c)

b)

a)

dyn

dyn

dyn

Ionospheric disturbance dynamo

Westward deviation

DH <0

Regular ionospheric dynamo

Eastward electrojet

DH >0

For selected events

Planetary magnetic signature of the sttorm wind disturbance dynamo

Currents : Ddyn, Le Huy and Mazaudier, JGR 2008,Vol 113, A0321

Fambitakoye et al, JGR 1990, 95, A9, 209-218

INTERMAGNET

DD

Ddyn = DH-SR-DR

ASIA

EUROPE

AMERICA

Equatorial Disturbance Dynamo Electric Fields

Fejer et al., 1983GRL, Vol 10, N°7, 537-540

PPE

DD

DD

Mayaud, JGR 1980Comment on the IonosphericDisturbance dynamo

Blanc JGR 1983Magnetospheric convectionEffects at midlatitudes1. Sai nt-Santin ObservationsVol 88, P. 211

Modeling storm-time electrodynamics of the low-latitude ionosphere-

thermosphere system , Maruyama et al., JASTP 2007, 69 1182-1199

Numerical simulations based on a combination of first principles models

Peymirat et al, 1998JGR, 103, A8, 17467-17478IMM + TIEGCM

DD + PPE

Modeling storm-time electrodynamics of the low-latitude ionosphere-

thermosphere System, Maruyama et al., JASTP 2007, 69 1182-1199

DD + PPE

Jicamarca

magnetometers

Peruviansector

Asiansector

Philippinessector

Storm effect on TEC Prompt penetration of the magnetospheric convection electric field

and ionospheric and disturbance dynamo

Images du satellite SOHO/NASA

CME

Maps of the TEC over Asia

Amory-Mazaudier et al, 2006

Coronal mass ejectionaffect the equatorial fountain

Equatorial fountain

Studies in Africa 2010-2014

Mene et al., Annales Geophysicae, 2011 STATISTICAL STUDY OF THE DP2

Current System

Côte d’Ivoire -> PhD in 2013

Nishida, 1968

Latitudinal profile of DP2

Mene et al.,

Annales Geophysiace, 2011

Enhancement of DP2 in the Three

Longitude sectors

Zaka et al, Annales Geophysicae, 2010

Zaka et al., JGR 2011 PhD on the Ionospheric Disturbance Dynamo in 2010

Zaka et al., JGR 2011

Coronal hole April 05, 2010

Coronal hole

April 06, 2010

Coronal hole

April 04, 2010Solar event :

coronal hole -> April 2010

High speed solar wind streams

Earth

46

SSC at 08:26

Shimeis et al., JGR 2012

SSC at 8.26

dashed lines : the magnetic quiet time variation

April 2010

3 4 5 6 7 9 108

TEC

DIDP2 + Ddyn

IEF

DH

At the beginning of the storm

-> Prompt penetration of the magnetospheric

electric field, (Vasyliunas, 1970)

DP2 (Nishida, 1968)

Three hours after the beginning of the storm

-> ionospheric disturbance dynamo (Blanc and

Richmond, 1980) is acting at low latitudes

Ddyn (Le Huy Minh and Amory-Mazaudier, 2005, 2008)

DI = DH –SR –DR (Dst)

Planetary signature of the ionospheric disturbance dynamo April 1 to 10, 2010

Fathy et al., JGR 2014

DH= SR+ DR+ Diono Diono = DP2 + Ddyn

DH= SR+ DR+ Diono with Diono = DH – SR- DR

Diono = DP2 + Ddyn

SR Ionospheric dynamo / regular variation

DR Solar wind magnetosphere dynamo/ ring current

Diono Solar wind magnetosphere dynamo/ Ionospheric disturbance

DP2 Ionospheric disturbance/ Prompt penetration [E]

Ddyn Ionospheric disturbance/ Ionospheric disturbance dynamo [Vn -> E]

Regular variationDiono = DH-SR-DR

Diono = DP2 + Ddyn

Ddyn

illustration of the continuous wavelet transformation of PHU station (a), ASW station (b)

and SJG (c) . The vertical axis illustrates the period of the signal in hours and the

horizontal axis is the universal time in hours. It's clear that the dominant frequency of the

signal around the period of 22 hours in the time interval from (45-125hrs) as it is clear from

the color index

Phu Thuy / Vietnam

San Juan/Porto Rico

Aswan : Egypt

• ZAKA Komenan -> DD CÔTE D’IVOIRE

• PhD -> Université de Cocody, le 11 février 2010.

• Zaka, K.Z., et al.Latitudinal profiles of the ionosphericdisturbance dynamo magnetic signat, ure : comparison with the DP2 magnetic disturbance, Ann. Geophys., 27, 3523-3526, 2009

• Zaka et al., Simulation of electric field and current during the June 11, 1993 disturbance dynamo event : comparison with the observation, to appear in JGR 2010

• MENE N.M. -> PPE CÔTE D’IVOIRE

• PHD -> Université de Cocody, le 21 juin 2013

• MENE N.M., A. T. Kobéa, O. K. Obrou, K. Z. Zaka, K. Boka, C. Amory- Mazaudier and P. Assamoi, statistical study of the DP2enhancement at the dayside dip-equator compared to low latitudes, Ann. Geophys. pp 2225-2233, 2011.

•

•

• SHIMEIS A. -> PPE + DD EGYPTE

• PHD -> octobre 2014

• Shimeis, A., I. Fathy, C. Amory-Mazaudier, R.Fleury ,A.M.

Mahrous, K. Yumoto, K.Groves, 2012, Signature of the Coronal Holeon near the North Crest Equatorial Anomaly over Egypt during thestrong Geomagnetic Storm 5th April 2010, Journal of Geophys. Res.,Vol 117, A07309, doi:10.1029/2012JA0117753, 2012.

•

• FATHY I. -> DD EGYPTE

• PHD -> Début 2015

• Fathy, I., C. Amory-Mazaudier, A. Fathy, A.M. Mahrous, K. Yumotoand E. Ghamry, Ionospheric disturbance dynamo associated to acoronal hole:Case study 5-10 April 2010, Journal of Geophys. Res.10.1002/2013JAO19510, 2014.

Conclusions• PPE : Prompt Penetration of the Electric field

• PPE -> the well known convection cells are reproduced with data , assimilation procedure /AMIE and models

• Shielding (30’) -> overshielding (several hours) , are related to field aligned current

• Disturbance Dynamo

• Magnetic signature Ddyn isolated in 2005 and extracted in 2014

• At low latitudes, Ddyn can be observed after several hours (2 or 3h)

• => long lasting disturbances are related to both Prompt penetration of magnetospheric electrique field and ionospheric disturbance dynamo

• TODAY : many data and models are available

– Solar wind and interplanetary medium data

– Localized in situ measurement -> radar

– Empirical models -> IRI, Neckquick, MSIS, radar data

– Physical Models (Rice, TIEGCM, CTIP …)

– Magnetic data

– Etc…

- We are doing case studies mixing all these models anddata but statistical studies are missing

- Wind data are still missing as well as directmeasurements of in situ electrodynamics parameterswith a good spatial coverage

- Classification of the case studies and statisticalanalysis are necessary

Need of an incoherent scatter radar in AFRICA