Research Output 2003 2017

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Article
2017
1 Citation (Scopus)

An application of principal component analysis to the interpretation of ionospheric current systems

Alken, P., Maute, A., Richmond, A. D., Vanhamäki, H. & Egbert, G. D., May 1 2017, In : Journal of Geophysical Research: Space Physics. 122, 5, p. 5687-5708 22 p.

Research output: Contribution to journalArticle

ionospheric currents
principal components analysis
Principal component analysis
principal component analysis
Harmonic analysis
2016
11 Citations (Scopus)

Comparison of auroral ionospheric and field-aligned currents derived from Swarm and ground magnetic field measurements

Juusola, L., Kauristie, K., Vanhamäki, H., Aikio, A. & van de Kamp, M., Sep 1 2016, In : Journal of Geophysical Research A: Space Physics. 121, 9, p. 9256-9283 28 p.

Research output: Contribution to journalArticle

Magnetic field measurement
field aligned currents
swarms
magnetic fields
ionospherics
5 Citations (Scopus)

Electrodynamic structure of the morning high-latitude trough region

Vanhamäki, H., Aikio, A., Voiculescu, M., Juusola, L., Nygrén, T. & Kuula, R., Mar 1 2016, In : Journal of Geophysical Research A: Space Physics. 121, 3, p. 2669-2682 14 p.

Research output: Contribution to journalArticle

morning
electrodynamics
radar
Electrodynamics
troughs
6 Citations (Scopus)

Ionospheric conductances and currents of a morning sector auroral arc from Swarm-A electric and magnetic field measurements

Juusola, L., Archer, W. E., Kauristie, K., Burchill, J. K., Vanhamaki, H. A. & Aikio, A. T., Nov 28 2016, In : Geophysical Research Letters. 43, 22, p. 11,519-11,527

Research output: Contribution to journalArticle

auroral arcs
morning
ionospherics
electric field
sectors
4 Citations (Scopus)

Postmidnight ionospheric troughs in summer at high latitudes

Voiculescu, M., Nygrén, T., Aikio, A. T., Vanhamaki, H. A. & Pierrard, V., Dec 1 2016, In : Journal of Geophysical Research: Space Physics. 121, 12, p. 12,171-12,185

Research output: Contribution to journalArticle

troughs
polar regions
ionospherics
summer
trough
3 Citations (Scopus)

Stepwise tailward retreat of magnetic reconnection: THEMIS observations of an auroral substorm

Ieda, A., Nishimura, Y., Miyashita, Y., Angelopoulos, V., Runov, A., Nagai, T., Frey, H. U., Fairfield, D. H., Slavin, J. A., Vanhamaki, H. A., Uchino, H., Fujii, R., Miyoshi, Y. & Machida, S., May 1 2016, In : Journal of Geophysical Research A: Space Physics. 121, 5, p. 4548-4568 21 p.

Research output: Contribution to journalArticle

histories
history
expansion
interactions
Magnetic flux
1 Citation (Scopus)

Study of TEC fluctuation via stochastic models and Bayesian inversion

Bires, A., Roininen, L., Damtie, B., Nigussie, M. & Vanhamäki, H., Nov 1 2016, In : Radio Science. 51, 11, p. 1772-1782 11 p.

Research output: Contribution to journalArticle

Stochastic models
inversions
ionospherics
Electrons
electrons
2015
8 Citations (Scopus)

A method to derive maps of ionospheric conductances, currents, and convection from the Swarm multisatellite mission

Amm, O., Vanhamäki, H., Kauristie, K., Stolle, C., Christiansen, F., Haagmans, R., Masson, A., Taylor, M. G. G. T., Floberghagen, R. & Escoubet, C. P., Apr 1 2015, In : Journal of Geophysical Research: Space Physics. 120, 4, p. 3263-3282 20 p.

Research output: Contribution to journalArticle

swarms
electric field
ionospherics
Spacecraft
orbits
10 Citations (Scopus)

High-latitude ionospheric equivalent currents during strong space storms: Regional perspective

Juusola, L., Viljanen, A., Van De Kamp, M., Tanskanen, E. I., Vanhamäki, H., Partamies, N. & Kauristie, K., Jan 15 2015, In : Space Weather. 13, 1, p. 49-60 12 p.

Research output: Contribution to journalArticle

extreme event
magnetometer
density current
solar cycle
magnetic field

Skew ray tracing in a step-index optical fiber using geometric algebra

Ang, A. S., Sugon, Q. M. & McNamara, D. J., Apr 20 2015, In : Applied Optics. 54, 12, p. 3764-3773 10 p.

Research output: Contribution to journalArticle

Ray tracing
ray tracing
Algebra
Optical fibers
rays
5 Citations (Scopus)

Solar wind control of ionospheric equivalent currents and their time derivatives

Juusola, L., Kauristie, K., Van De Kamp, M., Tanskanen, E. I., Mursula, K., Asikainen, T., Andréeová, K., Partamies, N., Vanhamäki, H. & Viljanen, A., Jun 1 2015, In : Journal of Geophysical Research: Space Physics. 120, 6, p. 4971-4992 22 p.

Research output: Contribution to journalArticle

Solar wind
electrojets
magnetic fields
electrojet
ionospherics
2014
5 Citations (Scopus)

Approximate forms of daytime ionospheric conductance

Ieda, A., Oyama, S., Vanhamäki, H., Fujii, R., Nakamizo, A., Amm, O., Hori, T., Takeda, M., Ueno, G., Yoshikawa, A., Redmon, R. J., Denig, W. F., Kamide, Y. & Nishitani, N., Dec 2014, In : Journal of Geophysical Research: Space Physics. 119, 12, p. 10397-10415 19 p.

Research output: Contribution to journalArticle

Plasma sources
zenith angle
daytime
ionospherics
Electric conductance
12 Citations (Scopus)

Statistical comparison of seasonal variations in the GUMICS-4 global MHD model ionosphere and measurements

Juusola, L., Facskõ, G., Honkonen, I., Janhunen, P., Vanhamäki, H., Kauristie, K., Laitinen, T. V., Milan, S. E., Palmroth, M., Tanskanen, E. I. & Viljanen, A., Oct 1 2014, In : Space Weather. 12, 10, p. 582-600 19 p.

Research output: Contribution to journalArticle

ionosphere
seasonal variation
electrojet
magnetic field
magnetosphere
2013
4 Citations (Scopus)

Deriving the geomagnetically induced electric field at the Earth's surface from the time derivative of the vertical magnetic field

Vanhamäki, H., Viljanen, A., Pirjola, R. & Amm, O., 2013, In : earth, planets and space. 65, 9, p. 997-1006 10 p.

Research output: Contribution to journalArticle

Earth surface
electric field
magnetic field
electric fields
magnetic variations
5 Citations (Scopus)

General solution for calculating polarization electric fields in the auroral ionosphere and application examples

Amm, O., Fujii, R., Vanhamaki, H. A., Yoshikawa, A. & Ieda, A., Jan 1 2013, In : Journal of Geophysical Research: Space Physics. 118, 5, p. 2428-2437 10 p.

Research output: Contribution to journalArticle

Ionosphere
electric field
ionospheres
ionosphere
polarization
4 Citations (Scopus)

Illustration of Cowling channel coupling to the shear Alfven wave

Yoshikawa, A., Amm, O., Vanhamäki, H. & Fujii, R., Oct 2013, In : Journal of Geophysical Research: Space Physics. 118, 10, p. 6405-6415 11 p.

Research output: Contribution to journalArticle

cowlings
Shear waves
electric field
magnetohydrodynamic waves
shear stress
7 Citations (Scopus)

Theory of Cowling channel formation by reflection of shear Alfven waves from the auroral ionosphere

Yoshikawa, A., Amm, O., Vanhamäki, H., Nakamizo, A. & Fujii, R., Oct 2013, In : Journal of Geophysical Research: Space Physics. 118, 10, p. 6416-6425 10 p.

Research output: Contribution to journalArticle

cowlings
Hall currents
field aligned currents
Ionosphere
Shear waves
2012
2 Citations (Scopus)

An application of the finite length Cowling channel model to auroral arcs with longitudinal variations

Fujii, R., Amm, O., Vanhamaki, H. A., Yoshikawa, A. & Ieda, A., Dec 7 2012, In : Journal of Geophysical Research: Space Physics. 117, 11, A11217.

Research output: Contribution to journalArticle

cowlings
auroral arcs
electric field
field aligned currents
Electric fields
6 Citations (Scopus)

Ionospheric Joule heating and Poynting flux in quasi-static approximation

Vanhamaki, H. A., Yoshikawa, A., Amm, O. & Fujii, R., Jan 1 2012, In : Journal of Geophysical Research: Space Physics. 117, 8, A08327.

Research output: Contribution to journalArticle

ionospheric heating
Joule heating
Fluxes
heating
heat
3 Citations (Scopus)

Polarization ellipse and Stokes parameters in geometric algebra

Santos, A. G., Sugon, Q. M. & McNamara, D. J., Jan 1 2012, In : Journal of the Optical Society of America A: Optics and Image Science, and Vision. 29, 1, p. 89-98 10 p.

Research output: Contribution to journalArticle

ellipses
Algebra
algebra
Polarization
polarization
2011
17 Citations (Scopus)
magnetosphere-ionosphere coupling
Ohms law
electrodynamics
reviewing
Maxwell equation
9 Citations (Scopus)
magnetosphere-ionosphere coupling
Magnetosphere
Ionosphere
Shear waves
shear stress
18 Citations (Scopus)

A statistical investigation of the Cowling channel efficiency in the auroral zone

Amm, O., Fujii, R., Kauristie, K., Aikio, A., Yoshikawa, A., Ieda, A. & Vanhamaki, H. A., Jan 1 2011, In : Journal of Geophysical Research: Space Physics. 116, 2, A02304.

Research output: Contribution to journalArticle

cowlings
auroral zones
radar
electric field
electrojet
4 Citations (Scopus)

Emission of cyclotron radiation by interstellar planets

Vanhamaki, H. A., Jul 1 2011, In : Planetary and Space Science. 59, 9, p. 862-869 8 p.

Research output: Contribution to journalArticle

cyclotron radiation
planets
planet
solar system
natural satellites
8 Citations (Scopus)

Inductive ionospheric solver for magnetospheric MHD simulations

Vanhamäki, H., Jan 19 2011, In : Annales Geophysicae. 29, 1, p. 97-108 12 p.

Research output: Contribution to journalArticle

ionospherics
electric field
simulation
electrodynamics
field aligned currents
27 Citations (Scopus)

Reformulation and energy flow of the Cowling channel

Fujii, R., Amm, O., Yoshikawa, A., Ieda, A. & Vanhamäki, H., Jan 1 2011, In : Journal of Geophysical Research: Space Physics. 116, 2, A02305.

Research output: Contribution to journalArticle

cowlings
Magnetosphere
energy flow
Electric fields
electric field
10 Citations (Scopus)

Self-consistent formulation for the evolution of ionospheric conductances at the ionospheric e region within the M-I coupling scheme

Yoshikawa, A., Nakamizo, A., Amm, O., Vanhamaki, H. A., Fujii, R., Tanaka, Y. M., Uozumi, T., Yumoto, K. & Ohtani, S., Jan 1 2011, In : Journal of Geophysical Research: Space Physics. 116, 9, A09223.

Research output: Contribution to journalArticle

ionospherics
field aligned currents
electrons
formulations
electron precipitation
2010
2 Citations (Scopus)

Oblique superposition of two elliptically polarized lightwaves using geometric algebra: Is energy-momentum conserved?

Sze, M. W. C., Sugon, Q. J. M. & McNamara, D. J., Jan 1 2010, In : Journal of the Optical Society of America A: Optics and Image Science, and Vision. 27, 11, p. 2468-2479 12 p.

Research output: Contribution to journalArticle

Algebra
Momentum
algebra
kinetic energy
plane waves
2009
11 Citations (Scopus)

Electrodynamics of an omega-band as deduced from optical and magnetometer data

Vanhamäki, H., Kauristie, K., Amm, O., Senior, A., Lummerzheim, D. & Milan, S., Dec 1 2009, In : Annales Geophysicae. 27, 9, p. 3367-3385 19 p.

Research output: Contribution to journalArticle

tongue
electrodynamics
magnetometer
magnetometers
electric field
2008
18 Citations (Scopus)

Towards understanding the electrodynamics of the 3-dimensional high-latitude ionosphere: Present and future

Amm, O., Aruliah, A., Buchert, S. C., Fujii, R., Gjerloev, J. W., Ieda, A., Matsuo, T., Stolle, C., Vanhamäki, H. & Yoshikawa, A., Nov 24 2008, In : Annales Geophysicae. 26, 12, p. 3913-3932 20 p.

Research output: Contribution to journalArticle

electrodynamics
polar regions
ionospherics
ionospheres
ionosphere
2007
9 Citations (Scopus)

A new method to estimate ionospheric electric fields and currents using data from a local ground magnetometer network

Vanhamäki, H. & Amm, O., Jan 1 2007, In : Annales Geophysicae. 25, 5, p. 1141-1156 16 p.

Research output: Contribution to journalArticle

magnetometer
electric current
magnetometers
ionospherics
electric field
19 Citations (Scopus)

Role of inductive electric fields and currents in dynamical ionospheric situations

Vanhamäki, H., Amm, O. & Viljanen, A., Jan 1 2007, In : Annales Geophysicae. 25, 2, p. 437-455 19 p.

Research output: Contribution to journalArticle

electric current
ionospherics
electric field
electric fields
field aligned currents
2006
8 Citations (Scopus)

New method for solving inductive electric fields in the non-uniformly conducting ionosphere

Vanhamäki, H., Amm, O. & Viljanen, A., Jan 1 2006, In : Annales Geophysicae. 24, 10, p. 2573-2582 10 p.

Research output: Contribution to journalArticle

ionospheres
electric field
ionosphere
conduction
electric fields
2005
8 Citations (Scopus)

Induction effects on ionospheric electric and magnetic fields

Vanhamäki, H., Viljanen, A. & Amm, O., Jan 1 2005, In : Annales Geophysicae. 23, 5, p. 1735-1746 12 p.

Research output: Contribution to journalArticle

ionospherics
electric field
induction
ionospheric currents
magnetic field
2004
6 Citations (Scopus)

A geometric algebra reformulation of geometric optics

Sugon, Q. J. M. & McNamara, D. J., Jan 1 2004, In : American Journal of Physics. 72, 1, p. 92-97 6 p.

Research output: Contribution to journalArticle

algebra
optics
rays
tracing
refraction
2003
38 Citations (Scopus)

One-dimensional upward continuation of the ground magnetic field disturbance using spherical elementary current systems

Vanhamaki, H. A., Amm, O. & Viljanen, A., Jan 1 2003, In : earth, planets and space. 55, 10, p. 613-625 13 p.

Research output: Contribution to journalArticle

disturbances
magnetic field
disturbance
ionospherics
magnetic fields