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  • 1.
    Alfvén, Hannes
    et al.
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Astrophysics in a Nutshell - from the Telescope to the Sputnik1988Report (Other academic)
  • 2.
    Alfvén, Hannes
    et al.
    KTH, Superseded Departments, Alfvén Laboratory.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory.
    Can the Big Bang Survive in the Space Age?1990Report (Other academic)
  • 3. Bahnsen, A.
    et al.
    Ungstrup, E.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fahleson, Ulf
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Olesen, J.K.
    Primdahl, F.
    Spangslev, F.
    Pedersen, A.
    Electrostatic Waves Observed in an Unstable Polar Cap Ionosphere1978In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol. 83, p. 5191-5197Article in journal (Refereed)
  • 4.
    Block, Lars P
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Mechanisms that may support magnetic-field-aligned electric fields in the magnetosphere1976In: ANNALES DE GEOPHYSIQUE, ISSN 0003-4029, Vol. 32, p. 161-174Article in journal (Refereed)
  • 5.
    Block, Lars P
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    The Role of Magnetic-Field-Aligned Electric Fields in Auroral Acceleration1990In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 95, p. 5877-5888Article in journal (Refereed)
  • 6.
    Block, Lars P
    et al.
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Lindqvist, Per-Arne
    KTH, Superseded Departments.
    Marklund, Göran
    KTH, Superseded Departments.
    Mozer, F. S.
    Pedersen, A.
    Measurement of Quasi-Static and Low Frequency Electric Fields on the Viking Satellite1987Report (Other academic)
  • 7.
    Block, Lars P
    et al.
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Lindqvist, Per-Arne
    KTH, Superseded Departments.
    Marklund, Göran
    KTH, Superseded Departments.
    Mozer, F. S.
    KTH, Superseded Departments.
    Pedersen, A.
    KTH, Superseded Departments.
    Potemra, T. A.
    KTH, Superseded Departments.
    Zanetti, L. J.
    Electric Field Measurements on Viking: First Results1987Report (Other academic)
  • 8.
    Block, Lars P
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lindqvist, Per-Arne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Marklund, Göran
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Mozer, F.S.
    Pedersen, A.
    Potemra, T.A.
    Zanetti, L.J.
    Electric field measurements on Viking - 1st results1987In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 14, p. 435-438Article in journal (Refereed)
  • 9.
    Block, Lars P
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Rothwell, P L
    Silevitch, M B
    Advantages of electric circuit models for treating the substorm breakup problem1998In: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol. 103, p. 6913-6916Article in journal (Refereed)
    Abstract [en]

    It is shown, by using a circuit model for the magnetospheric current system, that the substorm breakup can be triggered either by some instability anywhere in the circuit or by a decrease in the generator emf, i.e., a northward turning of the interplanetary magnetic field.

  • 10.
    Bohm, Martin
    et al.
    KTH, Superseded Departments, Alfvén Laboratory.
    Brenning, Nils
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Dynamic trapping: Neutralization of positive space charge in a collisionless magnetized plasma1990In: Physical Review Letters, ISSN 00319007, Vol. 65, p. 859-866Article in journal (Refereed)
    Abstract [en]

    It is shown by numerical simulations that in a collisionless plasma electron inertia leads to inefficient neutralization of positive space charge and allows large positive potentials (φ ≫ kTe/e) to be established and maintained on the time scale of ion motion. This is true even if the buildup of positive space charge is so slow that it corresponds to a small fraction of the random electron current of the surrounding plasma. A simple physical model clarifies the physics of the process and provides an analytical expression for the potential.

  • 11. Bohm, Martin
    et al.
    Brenning, Nils
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Dynamic trapping of electrons in the porcupine ionospheric ion beam experiment1992In: Advances in Space Research, ISSN 02731177, Vol. 12, p. 9-14Article in journal (Refereed)
    Abstract [en]

    Electrons are needed to maintain quasineutrality in a case where positive ions are injected across the magnetic field into a limited volume in a magnetized plasma. In the absence of collisions, a positive potential builds up and traps the electrons which enter the region along the magnetic field. If the added density of ions exceeds the ambient density, large potential differences along the magnetic field can be maintained this way. The process explains several features of the Porcupine xenon ion beam injection experiment, where strong magnetic-field-aligned electric fields were measured in the vicinity of a xenon ion beam which was injected into the ambient ionosphere from a spinning subpayload. © 1992.

  • 12.
    Bohm, Martin
    et al.
    KTH, Superseded Departments.
    Brenning, Nils
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Dynamic Trapping of Electrons in the Porcupine Ionospheric Ion Beam Experiment1990Report (Other academic)
  • 13.
    Brenning, Nils
    et al.
    KTH, Superseded Departments.
    Bohm, Martin
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Dynamic Trapping of Electrons in Space Plasmas1989Report (Other academic)
  • 14.
    Brenning, Nils
    et al.
    KTH, Superseded Departments, Alfvén Laboratory.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory.
    Dynamic trapping and skidding of dense plasma clouds2004In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 70, no 03-feb, p. 153-156Article in journal (Refereed)
    Abstract [en]

    We investigate the possibility that the mechanism dynamic trapping can play a role in decoupling dense plasma clouds injected in a thinner ambient plasma, by establishing strong magnetic-field-aligned electric fields in the vicinity or in the edge of the cloud. Dynamic trapping has previously been shown to allow such fields to be established and maintained on the time scale of ion motion, also for arbitrarily low current densities. A model is presented of how such fields could arise and decouple injected plasma clouds, a mechanism which we call dynamic decoupling. A dimensionless parameter. the dynamic decoupling factor F-DD, is derived which gives an estimate of the importance of the process. One possible application is the CRRES ionospheric injection experiments where anomalous skidding has recently been reported. However. the dynamic decoupling mechanism might also play a role in naturally occurring situations, e.g. the impulsive penetration of plasmoids from the solar wind into the Earth's magnetosphere.

  • 15.
    Brenning, Nils
    et al.
    KTH, Superseded Departments.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Bohm, Martin
    KTH, Superseded Departments.
    An Extension of the Boltzmann Relation to Collisionless Magnetized Plasma1990Report (Other academic)
  • 16.
    Brenning, Nils
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Haerendel, G.
    Kelley, M.C.
    Marklund, Göran
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Pfaff, R.
    Providakes, J.
    Stenbaek-Nielsen, H.C.
    Swenson, C.
    Torbert, R.
    Wescott, E.M.
    Interpretation of the Electric Fields Measured in an Ionospheric Critical Ionization Velocity Experiment1991In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 96, p. 9719-9733Article in journal (Refereed)
    Abstract [en]

    This paper deals with the quasi-dc electric fields measured in the CRIT I ionospheric release experiment, which was launched from Wallops Island on May 13, 1986. The purpose of the experiment was to study the critical ionization velocity (CIV) mechanism in the ionosphere. Two identical barium shaped charges were fired from distances of 1.99 km and 4.34 km towards a main payload, which made full three-dimensional measurements of the electric field inside the streams. There was also a subpayload separated from the main payload by a couple of kilometers along the magnetic field. The relevance of earlier proposed mechanisms for electron heating in CIV is investigated in the light of the CRIT I results. It is concluded that both the “homogeneous” and the “ionizing front” models probably apply, but in different parts of the stream. It is also possible that electrons are directly accelerated by a magnetic-field-aligned component of the electric field; the quasi-dc electric field observed within the streams had a large magnetic-field-aligned component, persisting on the time scale of the passage of the streams. The coupling between the ambient ionosphere and the ionized barium stream in CRIT I was more complicated than is usually assumed in CIV theories, with strong magnetic-field-aligned electric fields and probably current limitation as important processes. One interpretation of the quasi-dc electric field data is that the internal electric fields of the streams were not greatly modified by magnetic-field-aligned currents, i.e., a state was established where the transverse currents were to a first approximation divergence-free. It is argued that this interpretation can explain both a reversal of the strong explosion-directed electric field in burst 1 and the absence of such a reversal in burst 2.

  • 17.
    Brenning, Nils
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Haerendel, G.
    Kelley, M.C.
    Marklund, Göran
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Pfaff, R.
    Providakes, J.
    Stenbaek-Nielsen, H.C.
    Swenson, C.
    Torbert, R.B.
    Wescott, E.M.
    Critical ionization velocity interaction in the CRIT I rocket experiment1990In: Advances in Space Research, ISSN 02731177, Vol. 10, p. 63-66Article in journal (Refereed)
    Abstract [en]

    In the rocket experiment CRIT I, launched from Wallops Island on 13 May 1986, two identical Barium shaped charges were fired from distances of 1.3 km and 3.6 km towards the main experiment payload, which was separated from a sub-payload by a couple of km along the magnetic field. The relevance of earlier proposed mechanisms for electron heating in ionospheric critical velocity experiments is investigated in the light of the CRIT I results. It is concluded that both the "homogeneous" and the "ionizing front" models can be applied, in different parts of the stream. It is also possible that a third, entirely different, mechanism may contribute to the electron heating. This mechanism involves direct energization of electrons in the magnetic-field-aligned component of the DC electric field. © 1989.

  • 18.
    Brenning, Nils
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Haerendel, G.
    Kelley, M.C.
    Marklund, Göran
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Pfaff, R.
    Providakes, J.
    Stenbaek-Nielsen, H.C.
    Swenson, C.
    Wescott, E.M.
    Electrodynamic interaction between the CRIT I ionized barium streams and the ambient ionosphere1990In: Advances in Space Research, ISSN 02731177, Vol. 10, p. 67-70Article in journal (Refereed)
    Abstract [en]

    In the CRIT I Critical Velocity experiment, launched from Wallops Island on 13 May, 1986, two fast barium streams were ejected by means of shaped charges. Their electrodynamic interaction with the ambient ionosphere is discussed. An outstanding feature of the DC electric field observed within the streams was a large magnetic-field-aligned component, persisting on the time scale of the passage of the streams. One interpretation of the DC electric field data is that the internal electric fields of the streams is not greatly modified by Birkeland currents, i.e. a state is established, where the transverse currents are to a first approximation divergence-free. It is argued that this interpretation can explain why a reversal of the strong explosion-directed electric field was observed in the first explosion but not in the second (more distant one). © 1989.

  • 19.
    Fahleson, Ulf
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Pedersen, Arne
    Ionospheric temperature and density measurements by means of spherical double probes1974In: Planetary and Space Science, ISSN 00320633, Vol. 22, p. 41-66Article in journal (Refereed)
    Abstract [en]

    Rocket-borne double probes for electric field measurements can be intermittently operated in special, diagnostic modes involving current bias and low-impedance shunts to obtain information on the properties of the ambient ionospheric plasma along the flight path. Several such modes, and the information that they can provide, are analyzed. For example, in a low-impedance mode with asymmetric bias, the attenuation ratio (i.e. signal amplitude in this mode over the signal amplitude in the electric-field measuring mode) is in a simple way related to the electron temperature of the ambient plasma. The special surface coatings (Aquadag or vitreous carbon) normally used for electric field probes provide very homogeneous surface properties, a feature which also contributes to the reliability of the electron temperature measurements. In addition to electron temperature, the modes analyzed can be used to measure electron density and to give some information on ion temperature. The data from four rocket flights from ESRANGE are discussed in the light of these results. Electron temperature was measured in three of these flights. In all cases the temperature profile is in good agreement with theoretically predicted profiles based on the CIRA 1965 reference atmosphere and the solar illumination prevailing during the respective flights (twilight). Electron density profiles obtained by means of the double probe are in good agreement with the density measured by the Langmuir probe in the two flights for which both kinds of data are available. They are also in agreement with the electron density data available from ionosondes. Finally, pulses occurring when one of the probes passed through the rocket’s shadow, are used to determine the photoelectron yield of the probe coatings (Aquadag or vitreous carbon). The values obtained, (7 ± 3) × 10-6 A/m2 for Aquadag and (4 ± 2) × 10-6 A/m2 for vitreous carbon are in good agreement with expectations based on laboratory data and solar Lyman α radiation. © 1974.

  • 20.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Alfvén, Hannes1995In: Physics today, ISSN 0031-9228, E-ISSN 1945-0699, Vol. 48, p. 118-119Article in journal (Refereed)
  • 21.
    Fälthammar, Carl-Gunne
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Comments on the Motion of Magnetic Field Lines2006In: American Journal of Physics, ISSN 0002-9505, E-ISSN 1943-2909, Vol. 74, no 5, p. 454-455Article in journal (Other academic)
    Abstract [en]

    Belcher and Olbert recently showed that the concept of the motion of magnetic field lines can behelpful in teaching classical electromagnetism. Although this concept holds in many situations, ithas important limitations. It is shown that the most common definition, v=EB/B2, which is theone used by Belcher and Olbert, is not appropriate when an electrostatic field is present, unless thefield satisfies special conditions. In an infinitely conducting medium where the electric field has nocomponent parallel to the magnetic field, EB/B2 is still a meaningful definition of the motion ofmagnetic field lines which follow the plasma motion as if “frozen-in”. It used to be assumed thatspace plasmas could be treated as infinitely conducting and therefore the concept of magnetic fieldline motion was used extensively. But local nonvanishing values of E·B can “cut” magnetic fieldlines and invalidate the frozen-in condition.

  • 22.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Den joniserade materien - plasmat - i kosmos och i laboratoriet1978Report (Other academic)
  • 23.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Electric Fields in the Magnetosphere1989Report (Other academic)
  • 24.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Electric fields in the magnetosphere1982In: Advances in Space Research, ISSN 02731177, Vol. 2, p. 19-23Article in journal (Refereed)
  • 25.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Electric Fields in the Magnetosphere - a Review1988Report (Other academic)
  • 26.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Electric Fields in the Magnetosphere - the Evidence from ISEE, GEOS and Viking1988Report (Other academic)
  • 27.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Electric fields in the magnetosphere - the evidence from ISEE, GEOS, and Viking1989In: IEEE Transactions on Plasma Science, ISSN 00933813, Vol. v, p. 174-185Article in journal (Refereed)
    Abstract [en]

    Electric field measurements on the satellites GEOS-1, GEOS-2, ISEE-1, and Viking have extended the empirical knowledge of electric fields in space to include the outer regions of the magnetosphere. While the measurements confirm some of the theoretically expected properties of the electric fields, they also reveal unexpected features and a high degree of complexity and variability. The existence of a magnetospheric dawn-to-dusk electric field, as expected on the basis of extrapolation from low-altitude measurements, is confirmed in an average sense. However, the actual field exhibits large spatial and temporal variations, including strong fields of inductive origin. At the magnetopause, the average (dawn-to-dusk directed) tangential electric field component is typically obscured by irregular fluctuations of larger amplitude. In addition, data from electric-field measurements provide further support for the conclusion that a nonvanishing magnetic-field aligned electric field exists in the auroral acceleration region.

  • 28.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Electric fields in the magnetosphere- a review1989In: Planetary and Space Science, ISSN 00320633, Vol. 37, p. 899-914Article in journal (Refereed)
    Abstract [en]

    The satellites S3-3, GEOS-1, GEOS-2, ISEE-1 and Viking have extended direct measurements of electric fields to include the outer regions of the magnetosphere. The measurements confirm some of the theoretically expected properties of the electric fields. More importantly, they also reveal unexpected features and a high degree of complexity and variability. The existence of a magnetospheric dawn-dusk electric field has been confirmed in an average sense. However, the actual field exhibits large spatial and temporal variations, including strong fields of inductive origin. At the magnetopause the average (dawn-dusk directed) tangential electric field component is typlcally obscured by irregular fluctuations of larger amplitude. The magnetic field-aligned component of the electric field, which is of particular importance for ionosphere-magnetosphere coupling and for auroral acceleration is even now very difficult to measure directly. However, the data from electric field measurements provide further support for the conclusion, based on a variety of evidence, that a non-vanishing magnetic field-aligned electric field exists in the auroral acceleration region. © 1989.

  • 29.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Electric Fields in the Outer Magnetosphere - Recent Progress and Outstanding Problems1979Report (Other academic)
  • 30.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Electrodynamics of cosmical plasmas - some basic aspects of cosmological importance1990In: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 18, p. 11-17Article in journal (Refereed)
  • 31.
    Fälthammar, Carl-Gunne
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    From Magnetohydrodynamic Waves to Plasma Universe: Highlights of Hannes Alfvén’s Scientific Work2006In: Journal of History of Geophysics and Cosmical Physics, Vol. 7, no 1Article in journal (Refereed)
  • 32.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Generation mechanisms for magnetic-field-aligned electric fields in the magnetosphere1977Report (Other academic)
  • 33.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Generation mechanisms for magnetic-field-aligned electric fields in the magnetosphere1978In: JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY, ISSN 0022-1392, Vol. 30, p. 419-434Article in journal (Refereed)
  • 34.
    Fälthammar, Carl-Gunne
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Hannes Alfvén2007In: The Biographical Encyclopedia of Astronomers: Vol I A-L / [ed] Thomas Hockney, Springer, 2007, , p. 2p. 31-32Chapter in book (Refereed)
  • 35.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    In memoriam Hannes Alfven - (1908-1995)1995In: Astrophysics and Space Science, ISSN 0004-640X, E-ISSN 1572-946X, Vol. 234, p. 173-175Article in journal (Refereed)
  • 36.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Ionized Matter, Plasma, in the Cosmos and in the Laboratory1981Report (Other academic)
  • 37.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Laboratory and Near-Earth Space Plasma as a Key to the Plasma Universe1987Report (Other academic)
  • 38.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Laboratory and near-earth space plasma as a key to the plasma universe1988In: Laser and particle beams (Print), ISSN 0263-0346, E-ISSN 1469-803X, Vol. 6, p. 437-452Article in journal (Refereed)
  • 39.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory.
    Laboratory and Space Experiments as a Key to the Plasma Universe1993Report (Other academic)
  • 40.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Laboratory experiments of magnetospheric interest1974In: Space Science Reviews, ISSN 00386308, Vol. 15, p. 803-825Article in journal (Refereed)
    Abstract [en]

    Space-related laboratory experiments can play an important role as a complement to observations and active experiments in the magnetosphere. Excluding laboratory experiments for mere developing or testing of techniques for space experiments, we may distinguish between two major types: (1) partial scale model experiments and (2) experiments for clarifying basic plasma physical processes known or expected to be important in the magnetosphere (but without the ambition to simulate actual space configurations). The limitations and potentialities of both types are discussed and examples of experiments are given. It is concluded that there should be an increasing need for the experiments of the second type. In particular, they are needed for the clarification of the response of a thin plasma to electric fields and its ability to carry electric currents. This encompasses such key questions as the nature and role of ’anomalous’ resistivity (and electron runaway in its presence), the possible formation of double layers (and the acceleration processes associated with them) and rapid dissipation of magnetic-field energy. © 1974 D. Reidel Publishing Company.

  • 41.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory.
    Lars Block (1925-2002)2003In: EOS: Transactions, ISSN 0096-3941, E-ISSN 2324-9250, Vol. 84, no 1, p. 3-Article in journal (Other academic)
    Abstract [en]

    Lars Block, a pioneer in space plasma physics, died on 25 July 2002 at age 77.

    He will be remembered for important scientific contributions in areas ranging from plasma experiments in both the laboratory and in space, to theoretical research on fundamental plasma physics problems. His laboratory experiments were aimed at cosmic plasma physics problems such as modeling solar wind interaction with celestial bodies and anomalous interaction between plasma and neutral gas. His experiments in space were focused on electric fields above the aurora, and he played a key role in the Swedish space program, especially in the Viking project.

  • 42.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Magnetic-Field Aligned Electric Fields1983Report (Other academic)
  • 43.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory.
    Magnetic-field aligned electric fields in collisionless space plasmas: A brief review2004In: Geofísica Internacional, ISSN 0016-7169, Vol. 43, no 2, p. 225-239Article in journal (Refereed)
    Abstract [en]

    Magnetic-field aligned electric fields play an important role in the dynamics of magnetized plasmas. They allow decoupling of plasma elements by violation of the frozen field condition, breakdown of equipotential mapping, efficient acceleration of charged particles and rapid release of magnetic energy. In the collisionless plasmas that occupy most of the universe they used to be assumed nonexistent. A major consequence of the in situ measurements of the space age was the recognition that such electric fields do exist in the collisionless space plasma in spite of the absence of collisional friction. Indications of their existence came even from ground observations, but the final proof rests on the overwhelming evidence accumulated by in situ observations. These include observations of a number of characteristic features of particle distribution functions, various active experiments and direct measurements of electric fields. A number of mechanisms that can support magnetic field aligned electric fields have been identified. They include wave turbulence, solitary structures, magnetic mirrors, electric double layers and dynamic trapping. Some of them have been observationally confirmed to be important in the auroral process, but their relative roles are still not well known.

  • 44.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnetic-field-aligned electric fields1983In: ESA JOURNAL-EUROPEAN SPACE AGENCY, ISSN 0379-2285, Vol. 7, p. 385-404Article in journal (Refereed)
  • 45.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Magnetosphere-Ionosphere Coupling1985Report (Other academic)
  • 46.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments (pre-2005), Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnetosphere-ionosphere interactions - near-Earth manifestations of the plasma Universe1988In: Astrophysics and Space Science, ISSN 0004-640X, Vol. 144, p. 105-133Article in journal (Refereed)
    Abstract [en]

    As the Universe consists almost entirely of plasma, the understanding of astrophysical phenomena must depend critically on our understanding of how matter behaves in the plasma state. In situ observations in the near-Earth cosmical plasma offer an excellent opportunity of gaining such understanding. The near-Earth cosmical plasma not only covers vast ranges of density and temperature, but is the site of a rich variety of complex plasma physical processes which are activated as a result of the interactions between the magnetosphere and the ionosphere. The geomagnetic field connects the ionosphere, tied by friction to the Earth, and the magnetosphere, dynamically coupled to the solar wind. This causes an exchange of energy and momentum between the two regions. The exchange is executed by magnetic-field aligned electric currents, the so-called Birkeland currents. Both directly and indirectly (through instabilities and particle acceleration) these also lead to an exchange of plasma, which is selective and therefore causes chemical separation. Another essential aspect of the coupling is the role of electric fields, especially magnetic-field aligned (’parallel’) electric fields, which have important consequences both for the dynamics of the coupling and, especially, for energization of charged particles.

  • 47.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnetosphere-Ionosphere Interactions-Near-Earth Manifestations of the Plasma Universe1986In: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 14, p. 616-628Article in journal (Refereed)
  • 48.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnetospheric plasma interactions1994In: Astrophysics and Space Science, ISSN 0004-640X, E-ISSN 1572-946X, Vol. 214, p. 3-17Article in journal (Refereed)
    Abstract [en]

    The Earth’s magnetosphere (including the ionosphere) is our nearest cosmical plasma system and the only one accessible to mankind for extensive empirical study by in situ measurements. As virtually all matter in the universe is in the plasma state, the magnetosphere provides an invaluable sample of cosmical plasma from which we can learn to better understand the behaviour of matter in this state, which is so much more complex than that of unionized matter. It is therefore fortunate that the magnetosphere contains a wide range of different plasma populations, which vary in density over more than six powers of ten and even more in equivalent temperature. Still more important is the fact that its dual interaction with the solar wind above and the atmosphere below make the magnetosphere the site of a large number of plasma phenomena that are of fundamental interest in plasma physics as well as in astrophysics and cosmology. The interaction of the rapidly streaming solar wind plasma with the magnetosphere feeds energy and momentum, as well as matter, into the magnetosphere. Injection from the solar wind is a source of plasma populations in the outer magnetosphere, although much less dominating than previously thought. We now know that the Earth’s own atmosphere is the ultimate source of much of the plasma in large regions of the magnetosphere. The input of energy and momentum drives large scale convection of magnetospheric plasma and establishes a magnetospheric electric field and large scale electric current systems that carry millions of ampere between the ionosphere and outer space. These electric fields and currents play a crucial role in generating one of the most spectacular among natural phenomena, the aurora, as well as magnetic storms that can disturb man-made systems on ground and in orbit. The remarkable capability of accelerating charged particles, which is so typical of cosmical plasmas, is well represented in the magnetosphere, where mechanisms of such acceleration can be studied in detail. In situ measurements in the magnetosphere have revealed an unexpected tendency of cosmical plasmas to form cellular structure, and shown that the magnetospheric plasma sustains previously unexpected, and still not fully explained, chemical separation mechanisms, which are likely to operate in other cosmical plasmas as well.

  • 49.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    MHD Dynamo Action in Space Plasmas1984Report (Other academic)
  • 50.
    Fälthammar, Carl-Gunne
    KTH, Superseded Departments.
    Non-resistive electric potential drops in cosmic plasmas1978Report (Other academic)
123 1 - 50 of 108
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