# Presentation: 083303

## Geomagnetic Storms

***Vania K. Jordanova***
- Los Alamos National Laboratory, Space Science and Applications
- Los Alamos, NM 87545, USA

**U N C L A S S I F I E D**

**Geomagnetic Storms**

**•**   Solar and interplanetary origin of magnetic storms
**•**   What is a **geomagnetic storm**?
**•**   Sources, acceleration, and losses of ring current ions
**•**   Modeling the evolution of the terrestrial **ring current** using multi-satellite data

## Sun-Earth Connection

_***Questions:***_***  How and why does the Sun vary?***
***	******    ***_***How does the Earth respond?***_
***	******    ******What are the impacts on life and society?***

_**Varying output:**_**     ****	****         **
**•   ****Radiation**
**•   ****Solar Wind **
**•   ****Energetic Particles**
**Driven by 11 Year Solar Cycle**

***Earth***

***Variable Star***

**98        00        02        04        06        08        10        12        14        16        18   **

**Solar Flares**

**Geomagnetic Storms**

**Year**

**Sun-Earth Connection**

**Notes:**
What is the space environment we are studying?
It is well-known that the Earth is immersed in the varying output coming from the Sun in the form of radiation, solar wind, energetic particles
What we as scientists want to know is how the Earth responds to the solar variability
Besides the 11 year solar cycle, there are variation on shorter time scales that we are particularly interested in, these are geomagnetic storms

The Sun as a variable star emits varying output which affects the near-Earth environment
The Earth is immersed in the solar wind and is shielded by its magnetic field; the cavity containing the Earth’s magnetic field is called magnetosphere
We study how the Earth responds to the solar variability; the major magnetospheric response modes are geomagnetic storms and substorms

## •   The Earth’s magnetic field is dipolar only close to the surface
•   Solar plasma streams radially into space at high speed
•   The solar wind compresses the sunward side of the magnetosphere and drags out the nightside magnetosphere

**•**   Solar plasma streams radially into space at high speed
**•**   The solar wind compresses the sunward side of the magnetosphere and drags out the nightside magnetosphere

**The Shape of the Magnetosphere**

- Art by K. Endo, Nikkei Science Inc., Japan

## First Discovery by Explorer I, 1958

**First Discovery by Explorer I, 1958**

**VAN  ALLEN  RADIATION  BELTS**

## MOTION  OF  INDIVIDUAL  CHARGED  PARTICLES 

- SPIRALING

- SPIRALING AND BOUNCING FROM POLE TO POLE

- SPIRALING, BOUNCING AND DRIFTING FROM LINE TO LINE

- MOTION  OF  INDIVIDUAL  CHARGED  PARTICLES
- AROUND  EARTH’S  MAGNETIC  FIELD  LINES

- INCOMING CHARGED PARTICLES
- (ELECTRONS & PROTONS)

## Regions of the Magnetosphere

**Regions of the Magnetosphere**

## • Composition: e-, H+, He+, O+,  C+, N+, He++ 
• Energy Range:  ~ 1 keV < E < 300 keV
• Location:  ~ 2 < L < 8
• Energy Density:  ~ 10 - 1000 keV/cm3

**• ****Energy Range:  ~ 1 keV < E < 300 keV**
**• ****Location:  ~ 2 < L < 8**
**• ****Energy Density:  ~ 10 - 1000 keV/cm****3**

**main****	****recovery phase**

**Sudden **
**Commencement**

**Geomagnetic Storm: Ring Current Evolution**

## Dynamics of Geomagnetic Storms

** ****Variations lasting several days**
** ****Intensification of the ring current**
** ****Electron acceleration to MeV energies**
**=> Spacecraft anomalies**
**Key science questions:**
-  **Where do these particles come from?**
** ****What causes particle acceleration and loss?**
** ****What determines the effectiveness of the storm?**

- NOAA Data, 21-24 October, 2001

**Dynamics of Geomagnetic Storms**

**Notes:**
Geomagnetic storms represent long term variations
They are characterized by the intensification of energetic particles (1 keV to 300 keV) in the inner magnetosphere on the nightside
Often accompanied by the increase of fluxes of relativistic electrons
Which cause spacecraft disruptions

Key science questions we are looking at:
What is the cause for particle acceleration to relativistic energies – is it external (solar wind driven) or internal (local acceleration by plasma waves)?

## Dynamics of Magnetospheric Substorms

** ****Injection of hot plasma**
** ****Auroral brightening**
**=> Spacecraft charging**
**Key science questions:**
-  **What causes substorms to occur?**
** ****Where are the substorms initiated?**
** ****How are the particles energized?**
** ****What lights up the sky?**

- Spectacular Auroras at Earth

**Dynamics of Magnetospheric Substorms**

- (min)

- (min)

**Notes:**
Substorms are the magnetospheric response on even shorter time scales (min)
Hot ion and electron fluxes increase within minutes
Spectacular auroras are seen at Earth during substorms
The energetic fluxes cause spacecraft charging (space weather effect)

## Solar - Interplanetary - Magnetosphere  Coupling

**Solar - Interplanetary - Magnetosphere  Coupling**

**• ****Flow of plasma within the magnetosphere ****(convection) **

## Magnetospheric Electric Field

**Magnetospheric Electric Field**

- [Lyons and Williams, 1984]

-   Volland-Stern semiempirical model
-     convection potential:
-     corotation potential:
**    ****Drift velocity**:
-   Magnetic field model
**    ****Gradient-Curvature velocity**:

## Sources of Ring Current Ions

- [Chappell et al., 1987]

**max H****+**: solar min & quiet conditions
**max O****+**: solar max & active conditions
- Total ionospheric flux ~ **10**** ****26**** **ions/s
- => comparable to solar wind source

**• **Solar wind
**• **Ionosphere

## Ring Current Loss Processes

**Ring Current Belt**
**(1-300 keV)**
**Density Isocontours **

**Dawn**

**Dusk**

**Energetic**

**Neutral**

**Precipitation**

**Lower Density Cold**

**Plasmaspheric Plasma**

**(Dusk Bulge Region)**

**( L~6 )**

**( L~8 )**

**Plasmapause**

**( L~4)**

**Charge **

**Exchange**

**Ring Current Loss Processes**

## NASA IMAGE Mission:Imager for Magnetopause-to-Aurora Global Exploration 

## 05 UT

- 16 UT

- 08 UT

**IMAGE/HENA Proton Flux (27-39 keV) April 22**

## Ring Current Loss Processes

**Ring Current Belt**
**(1-300 keV)**
**Density Isocontours **

**Dawn**

**Dusk**

**Conjugate**

**SAR Arcs**

- Energetic

- Neutral

- Precipitation

**Anisotropic**

**Energetic**

**Ion Precipitation**

**Coulomb**

**Collisions**

**Between**

**Ring Currents**

**and**

**Thermals**

**(Shaded Area)**

**Lower Density Cold**

**Plasmaspheric Plasma**

**(Dusk Bulge Region)**

**( L~6 )**

**( L~8 )**

**Plasmapause**

**( L~4)**

- Charge

- Exchange

**Ring Current Loss Processes**

## •  Simultaneous global images of the plasmasphere and the ring current during the storm main phase (Dst= -133 nT) on May 24, 2000 [Burch et al., 2001]

**•**  The low altitude ENA fluxes peak near dusk and overlap the plasmapause [Burch et al., 2001]

**EUV** image of the plasmasphere at 0633 UT from above the north pole

- Superimposed **HENA** image of 39-60 keV fluxes showing significant ion precipitation near dusk

**IMAGE Mission: Seeing the invisible**

## Ring Current Loss Processes

**Ring Current Belt**
**(1-300 keV)**
**Density Isocontours **

**Dawn**

**Dusk**

- Conjugate

- SAR Arcs

- Energetic

- Neutral

- Precipitation

- Anisotropic

- Energetic

- Ion Precipitation

- Coulomb

- Collisions

- Between

- Ring Currents

- and

- Thermals

- (Shaded Area)

**Lower Density Cold**

**Plasmaspheric Plasma**

**(Dusk Bulge Region)**

**( L~6 )**

**( L~8 )**

**Wave Scattering  **

**of Ring Current Ions**

**Plasmapause**

**( L~4)**

**Isotropic Energetic Ion**

**Precipitation**

**Ion **

**Cyclotron **

**Waves**

- Charge

- Exchange

**Ring Current Loss Processes**

## Freja data, April 2-8, 1993 storm, Dst=-170 nT, Kp=8-
• Wave amplitudes decreased with storm evolution
• Waves below O+ gyrofrequency observed near Dst minimum [Braysy et al., 1998]

**Freja** data, April 2-8, 1993 **storm**, *Dst*=-170 nT, *Kp*=8**-**
**•**** **Wave** ****amplitudes**** **decreased with storm evolution
**•**** **Waves** ****below O****+**** gyrofrequency**** **observed near *Dst* minimum [Braysy et al., 1998]

- EMIC waves recorded using **DE1** magnetometer
- within 30° MLAT during the **10-year mission**
- lifetime [Erlandson and Ukhorskiy, 2001]

**EMIC Waves Observations**

## IMAGE FUV Data: Detached Proton Arcs

**IMAGE FUV Data: Detached Proton Arcs**

## Single particle motion - describes the motion of a particle under the influence of external electric and magnetic fields
	- trajectory tracing studies
	- mapping of distribution function
Magnetohydrodynamics and Multi-Fluid theory - the plasma is treated as conducting fluids with macroscopic variables, allow self-consistent coupling of the magnetosphere and ionosphere 

Kinetic theory - adopts a statistical approach and looks at the development of the distribution function for a system of particles

**	****- trajectory tracing studies**
**	****- mapping of distribution function**
**Magnetohydrodynamics**** and ****Multi-Fluid**** theory - the plasma is treated as conducting fluids with macroscopic variables, allow self-consistent coupling of the magnetosphere and ionosphere **
**	**
**Kinetic theory**** - adopts a statistical approach and looks at the development of the distribution function for a system of particles**

**Theoretical Approaches for Modeling Inner Magnetosphere Dynamics**

## Ring Current - Atmosphere Interactions Model

- PA= 0o – 90o
- dipole (*L*= 2.0-6.5)
- all MLT

** ****sources**

**  ****losses**

**Ring current model**

- plasma sheet - LANL

- charge exchange

- Coulomb collisions

- convection

**Plasmasphere model**

** ****transport**

- ionosphere/thermosphere

- atmospheric loss

- escape from MP

- RAM --- Jordanova et al. [1996; 2001]
-   Calculates the distribution function of ring current H+, O+, and He+   ions and thermal plasma from the fundamental kinetic equations

-  initial distribution - Polar

- w-p interactions

**Ring Current - Atmosphere Interactions Model**

## Storm-time Ring Current Simulations

**Storm-time Ring Current Simulations**

## Model: Drift of Ring Current Particles

**      ****Initial E=0.2 keV at L=10                 Initial E=0.4 keV at L=10**
**    ****The 90 deg pitch angle particle tracings. Asteriks are **
**                                          ****plotted at 1 hour steps within 20 hours                                          **

## Plasmasphere Model

**Ion composition: 77% H****+****, 20% He****+****, 3% O****+**

**Plasmasphere Model**

## Slide 26

## Slide 27

## Slide 28

## •  CME passage at Earth
•  Moderate geomagnetic storm on 10 January, 1997,
	Dst=-83 nT & Kp=6
•  Abundance of data available from ISTP spacecraft

**•****  **CME passage at Earth
**•**  Moderate geomagnetic storm on 10 January, 1997,
- 	Dst=-83 nT & Kp=6
**•****  **Abundance of data available from ISTP spacecraft

**WIND Data & ****Geomagnetic Indices**

## Slide 30

## Geosynchronous LANL Data: 10 January 1997

-  Hot ion fluxes are used to provide the time-dependent nightside boundary conditions of the model
-  MPA cold ion observations indicated the traversal of a dayside **plasmaspheric plume** in the afternoon LT sectors

**Geosynchronous LANL Data: 10 January 1997**

##  Enhanced electric fields are measured below L=5 during the main phase of the storm on the duskside (MLT18)
 Such electric fields appear about an hour or more before a strong ring current forms
 Much smaller electric fields at larger L shells (L=5-8) and on the dawnside (MLT6)
 Good agreement with the MACEP model we developed on the basis of the ionospheric AMIE [Richmond, 1992] model and a penetration electric field [Ridley and Liemohn, 2002]

** ****Enhanced electric fields** are measured below L=5 during the main phase of the storm on the **duskside **(MLT18)
-  Such electric fields appear about an hour or more before a strong ring current forms
-  Much **smaller electric fields** at larger L shells (L=5-8) and on the **dawnside** (MLT6)
-  Good agreement with the **MACEP** model we developed on the basis of the ionospheric **AMIE** [Richmond, 1992] model and a **penetration electric field** [Ridley and Liemohn, 2002]

- [Boonsiriseth et al., 2001]

**Convection Electric Field: Comparison with POLAR/EFI Data**

## Millstone Hill Radar Observations: Enhanced Electron Temperature, January 10, 1997

**Millstone Hill Radar Observations: ****Enhanced Electron Temperature, January 10, 1997**

## Model Results: Dst Index, Jan 10, 1997

**Comparison of:**
** ****•**** **Kp-dependent Volland-Stern model
-  **•** IMF-dependent model
- => An IMF-dependent model like MACEP predicts **larger electric field**, which results in  larger injection rate and **stronger ring current **buildup

- IMF dependent

## Ring Current Asymmetry

**•  **A very **asymmetric** ring current distribution during the **main** phase of the storm due to freshly injected particles on open drift paths
**•  **The total energy density peaks near **midnight** using **MACEP**, near **dusk** using **Volland-Stern**
**•  **Ring current ions **penetrate to lower L** shells and gain larger energy in **MACEP** than in Volland-Stern

**Ring Current Asymmetry**

## Effects of Collisional Losses

**Comparison of model results with POLAR data**

**Larger effect on:**
**   ****- postnoon spectra**
**   ****- low L shells**
**   ****- high magnetic latitudes**
**   ****- slowly drifting ~1-30 keV ions**

## Heating of Plasmaspheric  Electrons

**• ****Maximum heating** occurs initially on the nightside at **L~3.5** just inside the plasmapause
**• **It moves earthward to **L~2.75** with storm development
- => in agreement with **Millstone Hill radar observations**, indicating the predominant role of** ring current H****+**** **as a magnetospheric heat source

## Images from the proton imaging channel (SI-12) of the Far Ultraviolet Imager (FUV) at 12 minute intervals beginning at 21:02 UT on January 23.
Dashed contours indicate geomagnetic latitudes of 25°, 50°, & 75° 
	direction to the Sun
	detached arc

Characteristics of the events: subauroral arcs separated from the main oval and extending over several hours local time in the afternoon sector

- Dashed contours indicate geomagnetic latitudes of 25°, 50°, & 75°
- 	direction to the Sun
- 	**detached arc**
- Characteristics of the events: subauroral arcs separated from the main oval and extending over several hours local time in the afternoon sector

- [Immel et al., 2002]

**IMAGE FUV Data: ****Detached Arcs**

## IMAGE/FUV data on 23 January 2001; images in geographical coordinates and mapped into geomagnetic coordinates. The proton arc was observed from ~ 23 UT until ~24 UT after which the spacecraft began its perigee pass
Energy spectrograms of precipitating electrons and ions measured by the FAST electrostatic analyzer (energies <30 keV) conjugate to the IMAGE observations
Three peaks in the ion energy flux, no peaks in the electron energy flux equatorward of =-69.5° 
Consistent with DMSP observations of 3-30 keV proton precipitation above the detached arc and  <10 keV protons over the main oval 
 What causes this proton precipitation?

- Energy spectrograms of precipitating electrons and ions measured by the FAST electrostatic analyzer (energies **<30 keV**) conjugate to the IMAGE observations
- Three peaks in the **ion energy flux**, no peaks in the electron energy flux equatorward of =-69.5°
- Consistent with **DMSP** observations of 3-30 keV proton precipitation above the detached arc and  <10 keV protons over the main oval
-  What causes this **proton precipitation**?

**Observations of Detached Subauroral Proton Arcs**

## Subauroral Proton Arcs: Observations and Modeling

- Direct link between a subauroral arc (MLT=13 to ~16.5) and a global observations of a **plasmaspheric plume** by IMAGE [Spasojevic et al., 2004]

- RAM simulations: June 17-18, 2001

- Hours after 00 UT, June 17, 2001

- EMIC waves are excited in the afternoon MLT sector causing** ****intense ion precipitation**** **[Jordanova et al., 2007]

**Subauroral Proton Arcs: Observations and Modeling**

## Space Weather: How Does Solar VariabilityAffect Life and Society?

## Geomagnetic storms are among the most adverse space weather phenomena. To provide their accurate specification and forecasting:
• Develop an advanced understanding of the fundamental physical processes of the space environment from the Sun to Earth
• Integrate this understanding into physics-based models: 
solar wind
Earth’s magnetosphere
solar wind-magnetosphere coupling 

Physics-Based Models of the Space Environment at LANL:
• Building on more than 40 years of space science heritage at the Laboratory:
unique scientific expertise
exceptional computational capabilities
unique data to constrain and validate the models
• Support national security mission to maximize the safety of civilian and military satellites

**• **Develop an advanced understanding of the fundamental physical processes of the space environment from the Sun to Earth
**•**** **Integrate this understanding into physics-based models:
- solar wind
- Earth’s magnetosphere
- solar wind-magnetosphere coupling
***Physics-Based Models of the Space Environment at LANL:***
**• **Building on more than 40 years of space science heritage at the Laboratory:
- unique scientific expertise
- exceptional computational capabilities
- unique data to constrain and validate the models
**• **Support national security mission to maximize the safety of civilian and military satellites

** ****Conclusions**