New Aspects of Atmospheric and Space Electricity
Presiding: H Kikuchi, Institute for Environmental Electromagnetics; S Pulinets, Instituto de Geofisica
AE11B-01 INVITED 08:30h
EHD Approach to Tornadic Thunderstorms and Methods of Their Destruction
In many cases, tornadoes are accompanied or involved by lightning discharges and are thought to be com- posed of uncharged and charged components different from each other in terms of velocity, vorticity, heli- city, and appearance (shape and luminosity). Their visible dark portion may correspond to uncharged tor- nadoes, while luminous or bright part may involve charged tornadoes with return strokes. Usually, un- charged tornadoes have been considered to be ascending hot streams of thermohydrodynamic origin. This is the conventional theory of tornadoes, based on hydrodynamics (HD) or thermohydrodynamics (THD) but does not consider electrical effects that are really significant in tornadic thunderstorms..It has been shown, however, that a new electrohydrodynamics (EHD) established and developed over the last more than a decade is applicable to tornadic thunderstorms with lightning. This paper summarizes such an EHD approach and proposes the methods of tornado destruction based on EHD. Space charge and electric field configurations in tornadic thunderstorms are considered to be quadrupole-like, taking into account the cloud-charge images onto the ground. Accordingly, dynamics of particles and EHD flows in an electric quadrupole forming an electric cusp and mirror can straightly apply to those circumstances. When the gas pressure is below the breakdown threshold, there occur helical motion of particles, not only charged but also even uncharged, and/or vortex generation. While for gases whose pressure is beyond the breakdown threshold, the following basic processes succeed one after another. When the grain is uncharged, a dis- charge channel is formed towards each pole as a result of X-type reconnection. For a negatively or posi- tively charged grain, I-type reconnection occurs between the grain and positive or negative poles, respect- ively. For uncharged two grains, O-type reconnection between both grains could be involved in addition to X-type between each pole, while for oppositely charged two grains, F-type reconnection could be in- volved between grains in addition to I-type between each grain and a pole with opposite polarity. Thus one can say that the uncharged component of tornadic thunderstorms is composed of conventional ascending hot streams of thermohydrodynamic origin and particle flows of new EHD origin produced by a quadru- pole-like cloud-base, funnel-top charge distributions, while the charged component is a bunch of return strokes including charged flows due to dust-related electric reconnection and EHD vortices in large-scale generated by EHD helical turbulence where there may occur self-organization to coalescence of fluid vor- tex and electric displacement field lines at least in an initial stage of return stroke (rise time of some ms), since earth's magnetic field could be ignored. This also indicates that fluid vortex breakdown points also tend to merge electric cusps, X-type and O-type. Then the principle of dust-related electric reconnection could be replaced by dust cluster injection into electric cusps (X-type and O-type) in several ways just mentioned above. Thus a variety of such dust cluster injection could cause additional cloud-to-dust cluster discharges, expending electrostatic energy accumulated in thunderclouds considerably and destructing tornadoes consequently.
AE11B-02 INVITED 08:45h
Active Experiments on Artificial Air Ionization to Check the Physical Mechanism of Air Electrification by Radon in Seismically Active Area
The air ionization in troposphere leads to formation of the large charged clusters of the aerosol size due to water molecules attachment to the new formed ions. This process have several consequences leading to the changes of the air conductivity, formation of large scale space charges and large scale electric field, changes of the air temperature and relative humidity. All these effects were observed experimentally within the interval of two weeks before the strong earthquakes such as Colima earthquake in Mexico (M7.8) on 22 of January 2003 or Parkfield earthquake in USA (M6) on 28 of September 2004. In the case of earthquakes the atmosphere electricity modification is ascribed to the radon ionization and the effects are calculated within the frame of the seismo-ionosphere coupling model. But there are very few systematic sources of the radon monitoring, so the real check of the model is better possible within the frame of the controlled active experiment. Such experiments of the artificial ionization were conducted in Mexico using the large wire antennas producing the air ionization by applying the large electric potential (~ 40 kV) to the elevated circular thin wire of ~ 100 m diameter. It was demonstrated that such impact on the atmosphere can create the effects of the meteorological scale producing the artificial clouds (and rains), and even modify the large scale atmospheric formations as typhoons. Results of the theoretical estimations and active experiments will be demonstrated.
AE11B-03 INVITED 09:00h
General Instability of Clouds With Respect to the Formation of Horizontal Space Charge Layers
The origin of the multiple horizontal charge layers observed with balloons in the trailing stratiform region of mesoscale convective systems is explained through energy considerations and stability calculations inspired by he author's polarization catastrophe theory of atmospheric electricity [1]. We prove a cloud instability with respect to formation of horizontal polarization layers and space charge layers. Let n be the concentration of polarizable ice crystallites, each of them in the local field Eloc =E +P/3e, where E is macroscopic electric field in the cloud, e is vac. permitt., and P =np the cloud polarization, defined as the dipole moment per m3. Each crystallite has two charges +q and -q separated by the dipole length x. The average contribution of the dipole moment dipole moment p of an ice crystallite of mass M to the polarization vector is p=qx= AEloc=AF/q, where F is the force opposing the separation of the charges in the crystallite, A is polarizability. The work u' done to create the dipoles in the ice crystals per unit cloud volume is u'=n∫Fdx=(nqq/A)∫xdx=nqqxx/2A =npp/2A =PP/2nA. This increases the energy of the cloud, just like the energy of a set of extended springs. On the other hand, the cloud loses energy due to orientational polarization of the crystallites that tend to align themselves in a minimum energy direction in the local field u"=∫ElocdP=(E + P/3e)dP=∫PP/6e+∫EdP. The energy of the cloud is thus u=u'-u"=(pp/2)[n/A- nn/3e]. E also contains a polarization caused (depolarization) component that is largely compensated by the masking charges of ions attached to the regions where the divergence c(z) of P differs from zero, and will be neglected as is usual in the polarization catastrophe theory for stationary clouds [1]. The cloud polarization P in u" is usually well approximated [1] by the saturation polarization P=np, with p being the total dipole moment of each crystallite. Indeed, the author's polarization catastrophe criterion [1] is mmn>2.5 10exp21 cm-3, where m is the average number of water molecules in each crystallite. This criterion is satisfied in most clouds. However, our derivation is more general, and applicable for any kind of polarization of the individual crystallite. Let us apply to all crystallites in the cloud a local field of small virtual displacements in the z direction X'(z, t) = X(t)sin kz, with an arbitrarily small amplitude X(t). The whole cloud that was assumed to be initially homogeneous [X(0)=0], with concentration n(z)=N assumed to be initially constant over the whole cloud, from z=0 at the cloud base, to z =h at cloud top. Then, from the equation of continuity, we obtain in first order the concentration perturbation for crystallites n' = -(d/dz)(XN), i.e, n(z,t) = N-NX(t)kcoskz. Substituting into the expression U=(pp/2)∫[n/A-nn/3e]dz, of the cloud energy, its change U'=(pp/2)∫[-(NX/A)kcoskz+(2X/3e)kcoskz -(XXkkNN/3e)cos2kz]dz. Integrating over z, we obtain, at least for k=2p'r/h with integer r and p'=3.14, <coskz>=0, and <cos2kz>=1/2. We obtain an energy change that is always negative: <U'>=-[(pXkN/2)2]/3e. Therefore, the creation of regions of enhanced polarization sandwiching regions of reduced polarization, lowers the cloud energy. This concludes our elementary proof. Rigorous proof starts from the Lagrangian L=∫Ldz =∫nM[(dX'/dt)2]dz/2-∫c(z)c(z')dzdz'/2 | z-z' | -(pp/2)∫[n/A-nn/3e]dz, L=<(M/2)N∫{[1-X(t)kcoskz][(dX/dt)2][(sinkz)2]-(pp/2)[n/A-nn/3e]}dz> -(NNpp/2)[n/A-nn/3e]-[(pXkN/2)2]/3e.The Lagrange equations yield an exponentially increasing solution X(t)=(Const)exp{pNkt/[(3)1/2][(m)1/2][(e)1/2]}. This proves the presence of the instability. [1] P.H. Handel, JGR 90, 5857 (1985); GRLett. 10, 1 (1983).
AE11B-04 09:15h
Derivation of the Motion of Ball Lightning in the Maser-Soliton Theory
The motion of ball lightning (BL) in open air, in buildings, or in airplanes is explained here on the basis of the phase differences between the harmonic wave components that make up the soliton. Consider the quasi-stationary state of ball lightning in open air, on flat terrain. In general, the occupation of the energy levels that are subject to possible population inversion due to a sudden, large, but short electric field pulse caused, e.g., by lightning, will not be perfectly uniform. As seen from the location of the BL, the population inversion may be slightly stronger in a km3 on one side (&35;1) of the BL, than in a similar volume on the other side (&35;2) of the BL. The gradient g of the population inversion points towards &35;1. In particular, the waves originating in region &35;1 with k parallel to g, will be superposed on those coming from region &35;2, forming a standing wave E = Eoexpi[k.r-(W+s)t] + Eoexpi[-k.r-(W-s)t]. Here W is the average frequency in the maser. This frequency is lower due to damping. For population inversion it is higher. If the BL is in the middle of the maser region, we denoted by s the small deviation of the frequency W+s of the waves in the &35;1 region from its average, W. Then -s is the deviation from w in the &35;2 region. We can define the component parallel to k of a vector V, such that s = k.V; or Vk = s/k. Then, the elementary standing wave becomes E =Eoexpi[k.(r- Vt)-Wt] +Eoexpi[-k.(r- Vt)-Wt] =2Eo{cos[k.(r- Vt)]}expiWt. This is a standing wave that is moving with a velocity Vk =s/k. The component of V perpendicular to k is left arbitrary, depending on boundary conditions. Choosing the origin of the coordinates at the location of the BL, for s=0 we can express the total wave, including the BL, in terms of a cosine-Fourier integral packet of standing waves, Etot =IntegralE(k)cosk.r d3x, centered on the origin. With s nonzero, Etot = IntegralE(k)cos[k.(r -Vt)]d3x, and the BL will move with velocity v opposite to the gradient of the population of levels. In general, therefore, we conclude that BL tends to move away from the region of larger population inversion, or towards the region with larger absorption coefficient. This formulation can be done in terms of the dielectric constant er and quantum mechanical matrix elements. The permittivity is e=e0[1 + C(W)]=e0[1 + C`(W) + iC"(W)]. The susceptibility introduced by a population inversion Nn-Nm per unit volume on a molecular transition of frequency Wmn and damping G is C(W) = -3i[qqFnm(Nn-Nm)]/{Me0Wmn[Grad +2i(W-Wmn)]}, where Grad =1/Trad must be replaced by the total linewidth DWmn to include all forms of broadening. The oscillator strength Fmn= 4pMWmnRmn2/3h =Trad /Tmn is related to the molecular quantum mechanical matrix element Rnm the real molecular damping rate Tmn for electron charge q, mass M. The phase velocity is v=c/n=c/(er)1/2. Therefore, for C≪1 it can be written as v=Re[c/(1+C'/2+iC"/2)]=c[(1+C'/2)]/[(1+C'/2)2+C"C"/4]=[c/(1+ C'/2)]{1 - C"C"/4(1+C'/2)2; s=-cC"C"/4(1+C'/2)3 - >-cC"2/4(1+C'/2)3>, Vk = sk/kk. The small difference present in W=kv is given by the term C". The average < > is over the whole maser volume of many km3. Thus, we obtain Vk = s/k, and C'/2=3[Fnmqq(Nn-Nm)(W-Wmn)]/{Me0Wmn[(DWmn)2+4(W-Wmn)2]} C"=3[Fnmqq(Nn-Nm)Grad]/{Me0Wmn[(DWmn)2+4(W-Wmn)2]}. This is proportional to (Nn-Nm). The linear absorption/amplification coefficient is A =WC"/2c. For balanced maser conditions, the losses caused by the end reflection coefficient R must equal the maser gain: RRexp(-2AL)=1, or AL=logR. Therefore, we get C"=(2c/WL)logR. Substituting into Vk, Vk=-c[kC"2/4k(1+C'/2)3]=-[kc3(logR)/kWWLL(1+C'/2)3]=-(lamda/2pL)2[ck(log r)2/k(1+C'/2)3]. With lamda= 0.5 m, L =1 km, and (1+C'/2)3=2, this yields Vk= 1m/s, in agreement with observations.
AE11B-05 INVITED 09:30h
Saturn-Ring Simulation Experiment
We were able to generate the ring form in the laboratory by using two components fine particle plasmas (Dust Plasmas). This experiment will show one of the mechanisms of outer planets rings. The missions of Pioneer-10, 11, Voyager 1 and 2 revealed that micron and sub-micron size grains distribute spatially and that the Saturn rings were composed of small size dust particles. Dust particles are always charged by the influences of surrounding gaseous plasmas and UV radiations from the sun, so these particles are in the state of fine particle plasmas (dust plasmas). These particles prevail not only the influence of gravitational force only but the influence of electric and/or magnetic fields. This situation is believed and Mendis, Goertz et. al. investigated the dynamics of particles by introducing the gravitation and electrodynamics (gravito-electrodynamics). The gravitational force affects the influences charged and uncharged particles, equally. Charged particles (electric charge Q) are affected by F=Q(E+VXB), where V is particle velocity. Outer planets such as Saturn have magnetic fields like as earth, and these magnetized planets rotate around axis. The electric fields appear near a rotating magnetized sphere by an unipolar induction. Unipolar induction field E is given by E= -(wXr)XB using magnetic moment M of magnetized sphere at angular velocity w in a conducting medium (plasma). Within equatorial plane, B= - M/r3 and B=B0R3/r3, where R is the radius of planet and r is the distance from the center of the planet. This fields can be written as E=Pm/2r2T, by using Pm=4pr3B and T=2pw. The simulating condition can write as follows; where suffix S and M mean Saturn and miniature sphere, respectively. The created ring was located in the outskirts of the point from two to three times of sphere radius, and its thickness was very thin, and fine particle seem to rotate slowly around the sphere in same direction as rotation of sphere. The condition for creation was best fit with the estimated condition of simulation equation. Electric fields by unipolar induction is shown in Fig.2. It is clearly recognized that charged fine particles were trapped and co-rotated in the equatorial plane region. This fact indicates that the unipolar induction can play an important role for the ring creation of outer planets (Jupiter, Saturn, Uranus, and Neptune), in the early stage of solar system development.
AE11B-06 09:45h
Transient Currents in the Global Electric Circuit
Since the time of C.T.R. Wilson, thunderstorms have been viewed as the generators in the Earth's global electric circuit. Vonnegut, Moore, et al. [1966] showed that there were substantial electric fields above thunderstorm cores, which they attributed to holes in the cloud-top screening layer. These above-cloud fields are assumed to be important in driving currents between the cloud top and ionosphere in the global electric circuit. Vonnegut, Moore, et al. also showed that lightning flashes provide transient changes in the above-cloud electric field. We will present balloon measurements of electric field inside and above small, mountain thunderstorms and large, mesoscale convective systems. These measurements indicate that lightning transients sometimes enhance the above-cloud electric field magnitude, regardless of the presence or absence of a hole in the upper screening layer. We will also describe results from a one-dimensional model used to investigate the possibility that the above-cloud transient fields also play a significant role in the global circuit. Reference: Vonnegut, B., C. B. Moore, R. P. Espinola, and H. H. Blau, Jr., Electric potential gradients above thunderstorms, J. Atmos. Sci., 23, 764-770, 1966.