Supplementary material to “Energy Transfer in the Earth-Sun System”

A. T. Y. Lui, Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland; Y. Kamide, Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Aichi, Japan

Citation:
Lui, A. T. Y., and Y. Kamide (2007), Energy transfer in the Earth-Sun system, Eos Trans. AGU, 88(8), 98. [Full Article (pdf)]

Meeting Report on Earth-Sun System Exploration: Energy Transfer

The Conference on Earth-Sun System Exploration: Energy Transfer was held on January 16–20, 2006 at Kailua-Kona, Hawaii, USA. It was supported by The Johns Hopkins University Applied Physics Laboratory (JHU/APL), Solar-Terrestrial Environment Laboratory/Nagoya University (STEL), Committee on Space Research (COSPAR), International Association of Geomagnetism and Aeronomy (IAGA), National Aeronautics and Space Administration (NASA), National Science Foundation (NSF), Scientific Committee on Solar-Terrestrial Physics (SCOSTEP), and The 21st Century COE Program “Dynamics of The Sun-Earth-Life Interactive System” (SELIS).

The goal of this conference was to provide a forum for physicists engaged in the Earth-Sun system as well as in laboratory experiments to discuss and exchange knowledge and ideas on physical processes involving energy transfer. The motivation of this conference stemmed from the following realization. Space assets form an important fabric of our society, performing functions such as television broadcasting, cell-phone communication, navigation, and remote monitoring of troposphere weather. There is increasing awareness on how much our daily activities can be adversely affected by space disturbances tracing all the way back to the Sun. In some of these energetic phenomena, energy in various forms can propagate long distances from the solar surface to the interplanetary medium and eventually to the Earth’s immediate space environment, namely, its magnetosphere, ionosphere, and thermosphere. In addition, transformation of energy can take place in these space disturbances, allowing charged particle energy to be transformed to electromagnetic energy or vice versa. In-depth understanding on energy transformation and transmission in the Earth-Sun system will foster the identification of physical processes responsible for space disturbances and the prediction of their occurrences and effects.

Participants came from 15 countries in Asia (Japan, Korea, and Taiwan), North and South America (Brazil, Canada, and USA), Europe (Austria, Finland, France, Germany, Italy, Russia, Sweden, The Netherlands, and The United Kingdom). A total of 80 oral and 28 poster presentations were given in this conference. These presentations were sorted into five sessions:

Sun and Heliosphere,
Bow Shock, Magnetosphere, and Magnetotail,
Ionosphere and Thermosphere,
Storms and Substorms, and
Interdisciplinary Exchange.

The meeting opened up with an inaugural lecture by Dr. Syun-Ichi Akasofu highlighting some unsolved problems in the Earth-Sun system. For example, how can observations of a single isolated sunspot be compatible with Babcock’s model of emerging magnetic flux ropes under the photosphere? What are the sources of magnetic flux ropes observed in interplanetary space? The lecture was followed by presentations on the Sun and the heliosphere, covering the latest results on coronal mass ejections (CMEs), solar flares, solar energetic particle acceleration, intermittency in solar wind turbulence, and advanced reconstructions of CMEs. Three paradigms for solar eruptions (magnetic reconnection, kink instability, and injection of magnetic flux through the photosphere) were discussed in association with these presentations. Ed Cliver reported reconstructions of the solar cycle variations on solar wind parameters back to the year 1890 using the new long-term geomagnetic index called the Inter-Daily Variability while Leif Svalgaard derived the Dsv index, which could be used to estimate the interplanetary magnetic field (IMF) throughout the 20th century.

Significant progress has recently been made on large-scale numerical modeling of the Earth-Sun system. Models range from simple kinematic treatment (Ghee Fry) to a highly sophisticated “integrated” model (Tamas Gombosi) that encompasses many modules, each acting independently but tying to the rest of the chain. Robert Winglee and Mei-Ching Fok demonstrated the importance of incorporating ionospheric outflow and kinetic aspects in these models. Maha Ashour-Abdalla showed the usefulness of using large-scale kinetic models to trace the origins of magnetospheric particles.

Lev Zelenyi presented a novel description about the non-equilibrium state of the magnetotail to predict a universal power spectrum of fluctuations with a characteristic kink frequency. Vassilis Angelopoulos reported that fast plasma flows in the magnetotail could transfer energy either by directly penetrating to the inner magnetosphere or via the generation of Alfvén waves to reach the lower altitude. Jim Burch summarized the outstanding achievements with the IMAGE mission, followed by specific reports on global evolution of storm-time plasmasphere (Jerry Goldstein) and proton precipitation morphology (Steve Mende). Richard Thorne and Danny Summers gave detailed accounts of acceleration of radiation belt electrons by plasma waves. Geoff Reeves described a new radiation model called the Dynamic Radiation Environment Assimilation Model. Gerhard Haerendel proposed an elegant theoretical model for energy transfer in auroral arcs in which magnetic shear stress arising from interplay between pressure forces in the outer magnetosphere and frictional forces in the ionosphere causes field-aligned electric field and produces electron beams for auroral arcs.

Statistical analyses (Niescja Turner, Gang Lu and Xiaoyan Zhou) revealed clear distinctions between CIR-driven and ejecta-driven magnetic storms in geoeffectiveness, also between high-speed solar wind streams, CMEs, and interplanetary shocks. Yohsuke Kamide examined High-Intensity Long-Duration Continuous AE Activity (HILDCAA) events to show that substorms and enhanced convection contribute roughly equally to HILDCAA. There were several substorm presentations, including MHD simulation of reconnection generating traveling compression regions (Masayuki Ugai), current-driven instabilities (Mikhail Sitnov), evidence for two active regions during substorms (Gordon Rostoker), nonlinear shear ballooning instability (John Samson), trigger by solar wind discontinuities (Larry Lyons and Dae-Young Lee), physics-based substorm injection model (Mike Henderson), and a multiscale model using both fluid and particle simulations (Ling-Hsiao Lyu).

In the area of ionosphere and thermosphere, Jim Horwitz discussed the multiscale coupling processes in ionospheric plasma transport. Pat Newell reported a morning warm spot near 0830 MLT as a nearly symmetric partner of the afternoon hot spot in auroral precipitation at 1500 MLT. Both Janet Kozyra and Larry Paxton used TIMED observations to show unique features during intense storms in the ionosphere and thermosphere. Cora Randall noted that intense storms cause energetic particle precipitation affecting the middle atmosphere by producing odd nitrogen and odd hydrogen. The odd nitrogen so produced can descend to the stratosphere and participates in the catalytic cycles that control the global ozone distributions.

There were three presentations dealing with the general consideration of energy transfer. From comparison between theory and observations, Rickard Lundin noted the breakdown of the frozen-in condition occurring in localized as well as large-scale magnetospheric regions. Peter Yoon used first principles to show analytically that the efficiency of energy conversion in magnetic reconnection depends sensitively on the system size and geometrical configuration. Jim Drake proposed Fermi acceleration from shrinking magnetic islands in magnetic reconnection to be responsible for tremendous electron acceleration.

On the topics of novel analysis of the Earth-Sun system and interdisciplinary exchange, Tom Chang reviewed the basic concept of complexity in space plasmas. Giuseppe Consolini discussed application of nonequilibrium statistical thermodynamic approach to avalanching systems. Manfred Leubner demonstrated the cross-scale coupling in solar wind turbulence to be a fundamental consequence of non-extensive entropy and Abrahim Chian explained intermittent turbulence in terms of alternating switching between two unstable structures called chaotic saddles in the merged chaotic attractor. Walter Gekelman and Stephan Vincena showed the ubiquitous nature of Alfvén waves in laboratory plasma experiments. Syun-Ichi Akasofu gave a special presentation on global warming using very long-term historical records to show global warming existed even prior to the start of human industrialization, suggesting that the present global warming should not be automatically attributed to the greenhouse effect. This suggestion disturbed some environmentalists in the audience. Of great interest were two poster presentations by Gerald Duma and Friedemann Freud proposing ionosphere-induced telluric currents triggering earthquakes through conductivity enhancement in rocks from activating dormant electronic charge carriers as an explanation for the association between the occurrence frequency of earthquakes and the diurnal magnetic field variations at Earth due to ionospheric Sq currents.

The oral sessions for the meeting concluded with Don Mitchell’s presentation of fantastic energetic neutral atom images from Cassini to show substorm-like impulsive acceleration of oxygen in the Saturn’s magnetosphere. This serves as a reminder that fundamental plasma processes that we learn from studying the Earth-Sun system have applications to other planetary environments and to space plasmas in the Universe at large. More information about most of these presentations can be obtained from the meeting web site (http://esse.jhuapl.edu/).

In summary, this meeting truly reflects the breadth of the Earth-Sun system research since it encompasses investigations from the solar interior to the Earth’s subsurface. The participation of laboratory plasma physicists reveals the commonality of several outstanding plasma physics problems that both disciplines face in spite of vast differences in the values of the characteristic parameters in these plasma regimes.

A. T. Y. Lui: Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland 20723, USA
Y. Kamide: Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Aichi 442, Japan