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SNIPE Mission for Space Weather Research

(Small scale magNetospheric

and Ionospheric Plasma

Experiment)

Young-Sil Kwak

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Korea Astronomy & Space Science Institute (KASI)

SNIPE Introduction

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• Multi-satellite formation flying enables us to identify the temporal and spatial variations in space plasmas.
• Satellite: 6U CubeSat (10 kg) x 4
• KASI will launch the SNIPE spacecrafts in 2023.

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Scientific Instruments

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• Langmuir Probes

🡪 Ionospheric plasma density and temperature

• Solid State Particle Detector

🡪 precipitating energetic electrons

• Fluxgate Magnetometers

🡪 field-aligned current

• Gamma-Ray Burst Monitor

🡪 outer space hard X-ray

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Formation Flying

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• Satellite distances and formation flying shape

will be changed from 10 km to ~ 100 km.

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Along track

Cross track

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• Spatial scale and energy dispersion of electron microbursts

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• Temporal and spatial variations of plasma trough

• Temporal and spatial variations of electron density

and temperature in polar-cap patches

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• Coherence length of bubble/blob/MSTIDs

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• Large amplitude disturbance of field-aligned current

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Additional Science

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• Measuring EMIC waves at the top of ionosphere

• Main mission of SNIPE: to elucidate small-scale (10 km – 100 km) plasma structures in the topside ionosphere (below the altitude of 500 km)

SNIPE Science Objectives

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• Electron microburst generation process

• Chorus waves are discrete whistler mode waves.

THEMIS

observation

STSAT-1

observation

• Electron microbursts are electron precipitations having short durations (<~1 sec) at L=4-8 and 06-18 LTs.

• Wave-particle interactions scatter electron pitch angle and produce strong precipitation.

1. Electron Microbursts

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• EXPECTED RESULTS FROM THE SNIPE MISSION

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• How small electron precipitation structure exists and what is the mechanism of this precipitation phenomenon?

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• How does electron microburst interact with waves?

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• How large is the contribution of radiation belt loss due to the microburst precipitation?

1. Electron Microbursts

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• It is a persistent large-scale electron density depletion structure in mid-latitude F-region from the post-afternoon sector to the dawn sector.

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• It forms at the interface between the mid-latitude ionosphere and the high-latitude auroral region. It is pretended as narrow in latitude and extended in longitude.

2. Plasma Trough

• Mid-latitude plasma trough?

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• EXPECTED RESULTS FROM THE SNIPE MISSION

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• Plasma trough morphology, especially latitudinal and longitudinal small-scale (< 100 km) structures

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• Behavior of the small-scale temporal (< 1 sec) and spatial (10 km – 100 km) variations of the trough

2. Plasma Trough

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• EXPECTED RESULTS FROM THE SNIPE MISSION

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• Plasma trough morphology, especially latitudinal and longitudinal small-scale (< 100 km) structures

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• Behavior of the small-scale temporal (< 1 sec) and spatial (10 km – 100 km) variations of the trough

2. Plasma Trough

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• They are defined as 100 to 1000 km horizontal size regions with F-region plasma densities 2-10 times lager than the background density in the polar cap.

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• Plasma patches are produced by the plasma convection across the terminator and particle precipitation in the auroral region.

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• They are closely related to rapid fluctuations in radio signal amplitude and phase, called scintillation.

3. Polar-Cap Patches

• Polar-cap patches?

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• EXPECTED RESULTS FROM THE SNIPE MISSION

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The multiple satellite LPs observations with high sampling rates in high temporal

(< 1 sec) and spatial (10 km – 100 km) resolutions

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• Temporal variations of electron density and temperature in the polar-cap patches

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• The movement speed and growth disappearance process of the polar-cap patches

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• Spatial scale and spatial structure changes of the polar-cap patches.

3. Polar-Cap Patches

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• Bubble: plasma density depletion relative to the background
• Blob: plasma density enhancement relative to the background

• Bubbles/blobs

• MSTIDs: Medium-Scale Traveling Ionospheric Disturbances

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• TEC perturbation map

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4. Equatorial Plasma Bubbles/Blobs/MSTIDs

• Coherence length of bubbles and blobs

• As for the bubble coherence length, we expect to obtain SNIPE results like Xiong et al. [2016, Figure 5c] (https://earth-planets-space.springeropen.com/articles/10.1186/s40623-016-0502-5).

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• However, this figure was obtained from the Swarm satellite data during less than 2 months.

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• SNIPE mission will extend this result to a longer observation period and without close aliasing between the latitudinal and zonal inter-satellite distances.

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4. Equatorial Plasma Bubbles/Blobs/MSTIDs

• Whenever SNIPE pass through mid-latitude irregularities with small inter-satellite separation, we expect that the observed plasma density profiles look similar, but with certain offset caused by wavefront directions (see the following cartoon). If the offsets agree with the well-known directions of nighttime MSTID wavefronts, we can conclude that the topside signatures of nighttime MSTIDs do exist.

• Topside signatures of nighttime MSTIDs

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4. Equatorial Plasma Bubbles/Blobs/MSTIDs

• EXPECTED RESULTS FROM THE SNIPE MISSION
• Coherence length of bubbles/blobs/MSTIDs and their seasonal variations
• Wavefront directions of bubbles/blobs/MSTIDs and their seasonal variations

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4. Equatorial Plasma Bubbles/Blobs/MSTIDs

• Electromagnetic Ion Cyclotron (EMIC) Waves

• Transverse plasma waves generated by wave-particle interaction (ion cyclotron instability)

• Importance of EMIC Waves

• EMIC waves can interact resonantly with energetic ions and produce relativistic MeV electrons if Doppler-shifted wave frequency matches the particle cyclotron frequency
• Resonant particles may exchange energy and momentum with the waves and be accelerated along the background magnetic field and precipitate into the atmosphere while non-resonant particles sustain the wave oscillatory motion.

5. EMIC Waves

• Limitation of EMIC observation using single satellite

• It is difficult to interpret the spatial and temporal structure by single point observation.
• There was a limitation of instrumental capabilities in making sensitive magnetic field measurements.

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5. EMIC Waves

• EXPECTED RESULTS FROM THE SNIPE MISSION

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• Observations of EMIC waves in the lower frequency range below 0.2 Hz by using multi-satellites of SNIPE

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• Spatial characteristics such as spatial scale, latitudinal and longitudinal distribution, and durations of EMIC waves

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• Conjugate observation of wave propagation at the ground and multi-point satellite measurements

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• EXPECTED RESULTS FROM THE SNIPE MISSION

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• Characteristics of field-aligned current in Earth's aurora region

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• Statistical analysis of large amplitude magnetic perturbations

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• Verification of curlometer method to estimate current density by using multi-point observations

6. Field-Aligned Currents

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• In order to achieve the scientific goal of SNIPE, simultaneous observations from satellite and ground will be very effective.

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• EISCAT(European Incoherent SCATter scientific association)

: KASI has an affiliate membership

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• Polar region observations (by KOPRI, KASI)

: All-sky cameras, magnetometers, GPS scintillation monitor, VIPIR, etc.

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• Mid-latitude observations (by KASI)

: VHF ionospheric radar, magnetometer, all-sky camera, GPS TEC map

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• ERG mission (Japan)

SNIPE-ground conjunction observations

GDC Mothership/CubeSat Constellation

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• Mothership and CubeSats are launched on the same vehicle.

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• Mothership and CubeSats are deployed separately from the vehicle.

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• With the along track and cross track orbit maneuver, various formation could be realized.

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• The experience of SNIPE mission will enhance the multi-point observation of GDC mission.

• After successful launch of SNIPE, KASI will look for a new CubeSat mission.

Post-SNIPE (Proposal)

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Propose of SNIPE Data User Group

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• Because SNIPE is a low-cost science mission, the data may not be perfect for distributing to the general public as soon as receiving data. After verification, the data will be open to the general public, and we need several months for this job.

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• Nevertheless, we convince SNIPE will provide unprecedented data for geomagnetic storm research.

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• If you makes a user group for SNIPE data analysis, KASI will share the SNIPE data with them at the same level as Korean scientists.

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• We would like to propose a regular meeting with the user group to share the information on SNIPE instruments and operation.

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Thanks for your attention~!!

SNIPE

KASI Proprietary