Mona Kessel On detail at NASA GSFC missions and observables past, present, and future Measuring...

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Mona KesselOn detail at NASA GSFC

missions and observablespast, present, and future

Measuring Magnetosphericvariability

Ground-based

Space-based

Early Space ExplorationSputnik, October 1957

Explorer 1, January 1958 – First Discovery of the Space Age: Earth’s radiation beltsExplorer 2, 3, 4. Pioneer 1, 2, 3, ..

Exploration of the 1960’s

ATS 1-6 testing concepts in spacecraft design, propulsion, and stabilization, communication systemsDiscoverer 17 USAF photographic surveillance satellite assessing Soviet capabilities

Pioneer 6, 7, 8, 9Solar wind and magnetic field mapping in interplanetary spaceCosmic ray measurements and solar particle studies

COSMOS 2-261, Electron 1-4, Soviet satellites to study radiation belts, ionosphere, aurora

Explorer 5-35, study trapped radiation, ion and electron density & temperature, solar x-rayExplorer 15, study artificial radiation belt produced by Starfish high-altitude nuclear burst July 1962

Van Allen’s plot of Explorer 3 data in a hotel room on April 3, 1958

Explorer spacecraft made possible early studies of the radiation belts

Space Exploration 1970’s & 1980’s1973 IMP-8 measured magnetic fields, plasmas, energetic charged particles (e.g., cosmic rays) of Earth's magnetotail and magnetosheath and of the near-Earth solar wind. IMP operated 33 years in its 35 Earth Radii, 12-day orbit.

1975 GOES series of satellites measuring magnetic fields and particles in geosynchronous orbit, latest one in operation today.

1977 ISEE 1,2 investigate outermost boundaries of the Earth's magnetosphere, examine structure of solar wind near Earth and shock wave upstream, investigate cosmic rays and solar flare effects.

1978 ISEE 3 daughter of ISEE 1 with same goals as ISEE 1,2(1982 ICE) investigate magnetotail and conduct comet encounter

1981 DE investigated coupling between hot, tenuous, convecting plasmas of the magnetosphere and the cooler, denser plasmas and gases corotating in the earth's ionosphere, upper atmosphere, and plasmasphere.

1984 AMPTE CCE/UKS/IRM studied the access of solar-wind ions to the magnetosphere with lithium and barium tracer ions, 3 satellites to help distinguish between spatial structure and temporal changes.

1970’s Pioneer 10, 11, Voyager 1, 2 to Jupiter, Saturn and beyond.

ISEE-3

Voyager-1For more information go to http://nssdc.gsfc.nasa.gov/nmc/SpacecraftQuery.jsp

BowShock

IMP-8 spacecraft orbited around the Earth measuring fields and particles

Magnetopause

Finish

Magnetic field magnitude

Bulk ion speed

Bulk ion density

August 1985

Bow Shock Magnetopause

Day 221 = Aug 9

No particles?

IMP-8 made possible early studies around the magnetosphere

http://www-pi.physics.uiowa.edu/imp-data/

Low Energy Proton and Electron Differential Energy Analyzer (LEPEDEA) Spectrograms16 energy intervals between 5 eV and 50 keV. They had an angular field of view of 9° x 25°

Current Era Space Exploration

Geotail

Cluster

THEMISTWINS

RBSPMMS

What are the magnetospheric obervables?

• Magnetic Field

• Electric Field

• Ions

• Electrons

• Neutrals

Background/guiding fields;Waves - broad frequency range

Bulk parameters: density, speed, temperature;Counts/flux across broad energy range

• Photons Visible, UV, EUV, FUV

Space-based Ground-based

• Magnetic Field

Background fieldLow frequency waves

• Photons All Sky images

• Radars Ionospheric convection

from Russell, C., “The Magnetosphere,” in The Solar Wind and the Earth, eds. S. -I. Akasofu, Y. Kamide, pp. 73-100, Terra Scientific Publishing Company, Tokyo, 1987.)

The basic features of the Earth’s magnetosphere

& Radiation Belts& Ring Current

from Russell, C., “The Magnetosphere,” in The Solar Wind and the Earth, eds. S. -I. Akasofu, Y. Kamide, pp. 73-100, Terra Scientific Publishing Company, Tokyo, 1987.)

The basic features of the Earth’s magnetosphere

Cluster spacecraft made possible studies of the solar wind and bow shock.

Earth’s quasi-perpendicular shock is very thin.

& Radiation Belts

Cluster satellites

ZProton Density

Proton Speed (VX)

Proton Speed (Vy)

Proton Speed (Vz)

Magnetic Field

Electron Density

Artists’s conception of Earth’s

bow shock

Cluster satellites

Z Proton Density

Proton Speed (VX)

Proton Speed (Vy)

Proton Speed (Vz)

Magnetic Field

Electron Density

Earth’s quasi-parallel shock is thick and turbulent.

Cluster spacecraft made possible studies of the solar wind and bow shock.

ISEE made possible the study of the internal structure of the magnetopause.

Earth’s magnetopause is thick and multi-layered

Courtesy J. Dorelli

Earth’s aurora is a window into MI coupling

Polar’s view of auroral oval marks the boundary between open and closed field lines.

Earth’s magnetotail stores and releases energy.

IMP-8 spacecraft made possible studies of the magnetotail.

Earth’s radiation belt populations are energy dependent.

Van Allen Probes makes possible detailed study of the radiation belts.

Earth’s ring current is not a ring during storms.

IMAGE HENA made possible detailed study of the ring current.

Courtesy Liemohn, LWS SS

Earth’s inner magnetosphere makes a lot of waves.

Van Allen Probes makes possible detailed study of the inner magnetosphere.

Earth’s plasmasphere made visible with EUV

IMAGE spacecraft made observations from outside looking in at the plasmasphere.

Model courtesy of J. Goldstein

Sum up some basic knowledge

1. The bow shock slows, deflects, heat solar wind plasma2. The magnetopause is a barrier between solar magnetic field

and particles and magnetospheric fields and particles. It can be opened during reconnection; stay tuned!

3. The aurora gives us a window (through the filter of MI coupling) into global magnetospheric dynamics and plasma regimes.

4. The magnetotail stores and then explosively releases energy and low energy particles

5. The inner magnetosphere is home to 3 populations of particles that ebb and flow based on sources and losses

6. Outside looking in can reveal large scale structure and dynamics

Magnetospheric variabilityis dependent on Solar (Wind) Variability

1. Interplanetary magnetic field (IMF) direction2. Solar wind dynamic pressure (Pd)

What about variability?

Courtesy Kozyra, LWS Summer School

• Northward IMF: Produces cold dense plasma sheets which can be delivered into the inner magnetosphere if the IMF turns southward

• Southward IMF: Drives strong magnetic activity

Magnetopause – IMF direction - reconnection

Courtesy Dorelli, LWS Summer School

High geomagnetic activity(magnetospheric storms and substorms)

Low geomagnetic activity(fewer storms and substorms)

“Magnetopause phenomena are more complicated as a result of merging. This is why I no longer work on the magnetopause.” --J. W. Dungey

Spacecraft Observations are frequently interpreted in the context of the 2D Dungey cartoon

Measurements of magnetopause reconnection

Measure the “effects” of reconnection, e.g., flow.

Kessel et al., 1996

First observations of Reconnection effects under

northward IMF

Hawkeye spacecraft made possible the study of reconnection with N IMF.

Phan et al., 2003 Cluster and IMAGE spacecraft made possible the study of reconnection.

DeHoffman-Teller

analysis

Wal’en relation

Need evidence that the magnetopause is a rotational discontinuity:• deHoffman-Teller analysis• Wal’en relation

Aurora – window into global magnetospheric dynamics

Courtesy Donovan, LWS Summer School

It often makes sense to use ground-bases auroral (ionospheric) observations to remote sense magnetospheric dynamics

Alaska – Canada – Greenland – Scandanavia - Russia

Aurora

Ground-based magnetometer

chains can show global oscillations,

e.g., ULF waves.

Magnetotail – stores and then explosively releases energy

Nagai et al., 1998a

At 1107 UT on March 30, 1995, Geotail observed fast tailward flows at a speed of >600 km/s in the magnetotail at a radial distance of

15.5 RE. Tailward convection carrying southward magnetic fields was seen

near the neutral sheet.

Geotail spacecraft made possible studies of the magnetotail.

Geotail observations of a fast tailward flow at XGSM = -15 RE

Nagai et al., 1998bGeotail spacecraft made possible studies of magnetotail reconnection.

Geotail made the seminal observations of reconnection in the 23 RE region

Tailward probe ~ 11 RE

Inner probe ~ 9 RE

Dubyagin et al., 2011

Beginning of B perturbation

Dipolarization front

Flow bursts

Reconnection and inner magnetosphere are linked by short-lived flow bursts

THEMIS spacecraft made possible studies of the magnetotail.

Flow bursts penetrate into the inner magnetosphere

Kozyra, LWS Summer School 2010

~ Simultaneous double high-latitude reconnection results in large mass transfer from the solar wind into the closed field line region of the magnetosphere.

• Strong long-lived dawn-dusk electric fields associated with the passage of strong southward IMF by the Earth are the primary cause of magnetic storms.

• Energy is transferred to the magnetosphere via magnetic reconnection.• Convects plasma deep into the inner magnetosphere. Along the way it is

adiabatically and non-adiabatically energized to form the stormtime ring current. • Solar wind dynamic pressure enhances the geo-effectiveness.

Overwhelmingly, emphasis so far has been on the IMF direction as a driver of magnetospheric activity. But

solar wind dynamic pressure also has a role.

Recap – Magnetopause – Aurora – Magnetotail

Sudden solar wind pressure increase

causes inward motion of magnetopause

and subsequent loss of high energy electrons.

Turner et al.,2014b

southward

Inner magnetosphere – ebbs and flows based on sources and losses

ULF waves were correlated with the structure of the precipitation.

An azimuthal electric field impulse generated by magnetopause compression caused inward electron transport and minimal loss.

Chorus waves were responsible for most of the precipitation observed outside the plasmapause.

Chorus is excited following injection of 1-30 keV plasma sheet electrons into the inner magnetosphere during geomagnetically disturbed times. [Li et al., 2010]

Could chorus be excited by temperature anisotropy like EMIC?

BARREL

Halford et al., 2015

chorus

RBSPICE

B - 50 keV

A - 50 keV

Inner magnetosphere – ebbs and flows based on sources and losses

350 keV 1 MeV 3.5 MeV

Role of seed population and chorus waves Boyd, Spence et al., 2014

Source > L* 5.5

GOES seessubstorminjection

radial diffusionenhancement

Loss process

radial diffusionenhancement

LocalAcceleration

by chorusGOES seessubstorminjection

What is next?Instruments improving resolution and each time we learn something new(like better optics on a telescope resolve objects farther away)

Better time resolution, better energy resolution

Miniaturization - the trend to manufacture ever smaller mechanical, optical and electronic products and devices. More use of cubesats and smaller missions.

NASA recently launched the Magnetospheric Multiscale (MMS) Mission 4 spacecraft in close formation flight!

Mona Kessel On detail at NASA GSFC missions and observables past, present, and future Measuring...

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