Developing a VLF transmitter for LEO satellites:

Probing Of Plasmasphere and RADiation belts

- the POPRAD proposalJános Lichtenberger[1,2],Ondrej Santolik[3]; János Solymosi[4]; Luděk Graclík[5]; Fabien Darrouzet[6]; Andrei Demekhov[7]; Alexander Kudrin[8]; Nikolai Lehtinen[9]

[1] Department of Geophysics and Space Sciences, Eötvös University, Budapest, Hungary,[2] Geodetic and Geophysical Institute, RCAES, Sopron, Hungary,

[3] Institute of Atmospheric Physics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic

[4]BHE Bonn Hungary Electronics Ltd., Budapest, Hungary,

[5] G.L. Electronic Ltd, Brno-Medlánky, Czech Republic,

[6] Royal Belgian Institute for Space Aeronomy, Brussels, Belgium,

[7] Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia,

[8] Department of Radiophysics, University of Nizhny Novgorod, Nizhny Novgorod, Russia,

[9] Norwegian Center of Excellence Birkeland Center for Space Sciences, University of Bergen, Bergen, Norway

Developing a VLF transmitter for LEO satellites:

Probing Of Plasmasphere and RADiation belts

- the POPRAD proposalJános Lichtenberger[1,2],Ondrej Santolik[3]; János Solymosi[4]; Luděk Graclík[5]; Fabien Darrouzet[6]; Andrei Demekhov[7]; Alexander Kudrin[8]; Nikolai Lehtinen[9]

[1] Department of Geophysics and Space Sciences, Eötvös University, Budapest, Hungary,[2] Geodetic and Geophysical Institute, RCAES, Sopron, Hungary,

[3] Institute of Atmospheric Physics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic

[4]BHE Bonn Hungary Electronics Ltd., Budapest, Hungary,

[5] G.L. Electronic Ltd, Brno-Medlánky, Czech Republic,

[6] Royal Belgian Institute for Space Aeronomy, Brussels, Belgium,

[7] Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia,

[8] Department of Radiophysics, University of Nizhny Novgorod, Nizhny Novgorod, Russia,

[9] Norwegian Center of Excellence Birkeland Center for Space Sciences, University of Bergen, Bergen, Norway

Motivation Motivation

1. The extensive role of VLF waves in the dynamics of Geospace environment

2. Up to date, only a few examples of VLF transmitter have been flown/planned on satellites

3. None of them was/will be polar orbiting LEO satellite

1. The extensive role of VLF waves in the dynamics of Geospace environment

2. Up to date, only a few examples of VLF transmitter have been flown/planned on satellites

3. None of them was/will be polar orbiting LEO satellite

● Lightning whistlers: monitoring the cold plasma background, a basic parameter for wave-particle interaction (ground network: AWDANet, in-situ measurements: Van Allen Probes)

● VLF chorus and hiss: key role in acceleration and precipitation of high energy particles in the radiation belts

● Lightning whistlers: monitoring the cold plasma background, a basic parameter for wave-particle interaction (ground network: AWDANet, in-situ measurements: Van Allen Probes)

● VLF chorus and hiss: key role in acceleration and precipitation of high energy particles in the radiation belts

Motivation Motivation

1. The extensive role of VLF waves in the dynamics of Geospace environment2. Up to date, only a few examples of VLF transmitter have been flown/planned on satellites3. None of them was/will be polar orbiting LEO satellite

1. The extensive role of VLF waves in the dynamics of Geospace environment2. Up to date, only a few examples of VLF transmitter have been flown/planned on satellites3. None of them was/will be polar orbiting LEO satellite

Recent missions with active VLF antennas:● IMAGE RPI: 500m tip-to-tip dipole antenna, max.10W power● Cluster WHISPER: 88m tip-to-tip dipole antenna, max 250mW power● Active (Intercosmos-24) VLF-G: magnetic loop antenna, Ø=20m, 10kW power● Siple, Antarctica: 2x2x21km horizontal dipole antenna, 150kW input power

Upcoming missions: ● DSX WPIx: 80m tip-to-tip dipole antenna, max 500/900W power● TERSat: 5m tip-to-tip dipole antenna, max 32W power

TERSat is the only satellite planned to fly on LEO (low inclination) orbit

Recent missions with active VLF antennas:● IMAGE RPI: 500m tip-to-tip dipole antenna, max.10W power● Cluster WHISPER: 88m tip-to-tip dipole antenna, max 250mW power● Active (Intercosmos-24) VLF-G: magnetic loop antenna, Ø=20m, 10kW power● Siple, Antarctica: 2x2x21km horizontal dipole antenna, 150kW input power

Upcoming missions: ● DSX WPIx: 80m tip-to-tip dipole antenna, max 500/900W power● TERSat: 5m tip-to-tip dipole antenna, max 32W power

TERSat is the only satellite planned to fly on LEO (low inclination) orbit

Motivation Motivation

1. The extensive role of VLF waves in the dynamics of Geospace environment2. Up to date, only a few examples of VLF transmitter have been flown/planned on satellites3. None of them was/ will be polar orbiting LEO satellite

1. The extensive role of VLF waves in the dynamics of Geospace environment2. Up to date, only a few examples of VLF transmitter have been flown/planned on satellites3. None of them was/ will be polar orbiting LEO satellite

Polar LEO satellite and transmitted VLF waves Polar LEO satellite and transmitted VLF waves

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Science Objectives:

1. Systematic probing of the plasmasphere by coded VLF pulses - “artificial whistlers”:- the code contains the time of transmission, thus the time of the excitation (the most

uncertain parameter for whistler inversion)- the field line of the propagation is known from satellite position – it has to be estimated

during the whistler inversion process - existing ground based VLF receiver network (AWDANet) can be used to detect the

signals- polar orbit allows to monitor the plasmasphere at all magnetic latitude within 20 minutes

Science Objectives:

1. Systematic probing of the plasmasphere by coded VLF pulses - “artificial whistlers”:- the code contains the time of transmission, thus the time of the excitation (the most

uncertain parameter for whistler inversion)- the field line of the propagation is known from satellite position – it has to be estimated

during the whistler inversion process - existing ground based VLF receiver network (AWDANet) can be used to detect the

signals- polar orbit allows to monitor the plasmasphere at all magnetic latitude within 20 minutes

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Science Objectives:

2. Systematic probing of the energetic electron population - “artificial chorus/hiss”:- a transmitted frequency ramp between 1-10kHz can interact with the counter-streaming

electrons and precipitates them by pitch angle scattering into the atmosphere- an energetic electron detector – on the same or on different spacecraft – can

systematically survey the presence and energy of the population- operating this mode continuously along the orbit maps the energetic electron population

in the inner and outer radiation belts as well as in the slot region

Science Objectives:

2. Systematic probing of the energetic electron population - “artificial chorus/hiss”:- a transmitted frequency ramp between 1-10kHz can interact with the counter-streaming

electrons and precipitates them by pitch angle scattering into the atmosphere- an energetic electron detector – on the same or on different spacecraft – can

systematically survey the presence and energy of the population- operating this mode continuously along the orbit maps the energetic electron population

in the inner and outer radiation belts as well as in the slot region

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Science Objectives:

1. Systematic probing of the ionosphere by VLF pulses - “inverse fractional hop whistler or VLF TEC ”:- the pulses can propagate not only upward, but downward as well – fractional hop - the code contains the time of transmission, thus the time of the excitation (the most

uncertain parameter for whistler inversion)- the field line of the propagation is known from satellite position – it has to be estimated

during the whistler inversion process - existing ground based VLF receiver network (AWDANet) can be used to detect the

signals- the whistler-mode propagation in VLF range is more strongly affected by the magneto

-ionic medium than at higher frequencies (e.g GPS signal), thus the state of the ionosphere can be estimated more precisely.

Science Objectives:

1. Systematic probing of the ionosphere by VLF pulses - “inverse fractional hop whistler or VLF TEC ”:- the pulses can propagate not only upward, but downward as well – fractional hop - the code contains the time of transmission, thus the time of the excitation (the most

uncertain parameter for whistler inversion)- the field line of the propagation is known from satellite position – it has to be estimated

during the whistler inversion process - existing ground based VLF receiver network (AWDANet) can be used to detect the

signals- the whistler-mode propagation in VLF range is more strongly affected by the magneto

-ionic medium than at higher frequencies (e.g GPS signal), thus the state of the ionosphere can be estimated more precisely.

Polar LEO satellite and transmitted VLF waves Polar LEO satellite and transmitted VLF waves

Artificial whistler

Artificial chorus/hiss

Precipitated particle

„VLF TEC”

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Challenges:

1. The antenna efficacy in the ionosphere:

- high refractive index cf. to magnetosphere- dense plasma – plasma sheath around the antenna

Challenges:

1. The antenna efficacy in the ionosphere:

- high refractive index cf. to magnetosphere- dense plasma – plasma sheath around the antenna

Reinisch et al. SSR, 2000

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Challenges:2. What is the necessary powerChallenges:2. What is the necessary power

Distribution of total magnetic (top panel) and electric (bottom panel) wave power at 5kHz±50Hz for 665 half-hop whistlers recorded by the VAP (RBSP-B) satellite

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Challenges:2. What is the necessary powerChallenges:2. What is the necessary power

Distribution of total electric (left panel) and magnetic (right panel) wave power at 1kHz±50Hz for 3072 fractional-hop whistlers recorded by the DEMETER satellite

↓25 (μV/m)2 /Hz and 0.3· 10-6 nT2 /Hz at 1kHz artificial whistler10 (μV/m)2 /Hz and 0.15· 10-6 nT2 /Hz for 5kHz

100 (μV/m)2 /Hz and 10-6 nT2 /Hz at 2-4 kHz artificial chorus/hiss

Developing a VLF transmitter for LEO satellites Developing a VLF transmitter for LEO satellites

Challenges:

3. Electric dipole or magnetic loop?

Challenges:

3. Electric dipole or magnetic loop?

● Electric dipole: more widely used, but long wires need rotation to deploy

● Magnetic loop: compact, but difficult to deploy

● Electric dipole: more widely used, but long wires need rotation to deploy

● Magnetic loop: compact, but difficult to deploy

POPRADPOPRAD

Tasks:Tasks:

1. Theoretical and numerical modelling of ● electric dipole antenna embedded in the ionospheric plasma (between height of 600-

800km and for L-shells between L=1.5 and 8 RE)● magnetic loop antenna embedded in the ionospheric plasma (between height of 600-

800km and for L-shells between L=1.5 and 8 RE)

2. Designing two VLF transmitters – with electric/magnetic antenna

3. Manufacturing the test transmitters and antennas

4. Testing the manufactured transmitters and antennas in Krot

1. Theoretical and numerical modelling of ● electric dipole antenna embedded in the ionospheric plasma (between height of 600-

800km and for L-shells between L=1.5 and 8 RE)● magnetic loop antenna embedded in the ionospheric plasma (between height of 600-

800km and for L-shells between L=1.5 and 8 RE)

2. Designing two VLF transmitters – with electric/magnetic antenna

3. Manufacturing the test transmitters and antennas

4. Testing the manufactured transmitters and antennas in Krot

POPRADPOPRAD

Design and test principles: 1. Similarity transformation (Alfven&Falthammar)Design and test principles: 1. Similarity transformation (Alfven&Falthammar)

POPRADPOPRAD

Design and test principles: 2. Tests in Krot (Nizhny Novgorod, Russia)Design and test principles: 2. Tests in Krot (Nizhny Novgorod, Russia)

POPRADPOPRAD

Design and test principles: 2. Tests in Krot (Nizhny Novgorod, Russia)Design and test principles: 2. Tests in Krot (Nizhny Novgorod, Russia)

Conclusions and future plans Conclusions and future plans

1. POPRAD was submitted to COMPET-5-2016 call – but was not selected

2. We plan to resubmit it to FETOPEN-01-2016-2017 call

3. POPRAD can fly on dedicated Space Weather satellites/satellite constellation ( 3D tomography)

4. POPRAD can be a standard payload on future polar orbiting satellites (the European MetOp-SG, the US JPSS and DMSP satellites), perfectly complementing the SEM/MEPED instruments

1. POPRAD was submitted to COMPET-5-2016 call – but was not selected

2. We plan to resubmit it to FETOPEN-01-2016-2017 call

3. POPRAD can fly on dedicated Space Weather satellites/satellite constellation ( 3D tomography)

4. POPRAD can be a standard payload on future polar orbiting satellites (the European MetOp-SG, the US JPSS and DMSP satellites), perfectly complementing the SEM/MEPED instruments

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