Heating of heavy ions has been observed in the equatorial magnetosphere in GEOS 1 and 2 and ATS 6 data due to ion cyclotron waves generated by anisotropic hot ring current ions. A one‐dimensional hybrid‐Darwin code has been developed to study ion heating in the ring current. The mechanism for the heating of thermal hydrogen and helium by ion cyclotron waves has been studied previously in particle simulations of a bi‐Maxwellian plasma. Here, a strong instability and heating of thermal ions is investigated in a plasma with a loss cone distribution of hot ions. The linear growth rate calculation and particle simulations are conducted for cases with different loss cones and relative ion densities. The linear instability of the waves, the quasi‐linear heating of cold ions and dependence on the thermal H+/He+ density ratio are analyzed, as well as nonlinear parallel heating of thermal ions. Effects of thermal oxygen and hot oxygen are also studied.

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About eighteen thousand known variables were observed by LAMOST during the first stage of the spectroscopic survey from October 24, 2011 to July 16, 2017. Stellar atmospheric parameters for about eleven thousands of them were determined including the temperature (T), the gravitational acceleration (log g), the metallicity [Fe/H] and the radial velocity V r. Those parameters are introduced in the paper. The locations of those variables including δ Sct and γ Dor stars on the Log g-T diagram are presented where EA-and EW-type eclipsing binaries are also shown for comparison. Meanwhile, new photometric results on two special sample stars ROTSE1 J144111.82+382750.0 and CSS_J034112.5+035336 were obtained by follow-up observations. The former was originally found as a δ Sct with a period of 0.191291 days. However, the LAMOST parameters reveal that it is far beyond the red edge of pulsational instability trip of δ Sct stars. By using those new photometric data, we detect that is an EW-type eclipsing binary with an orbital period of 0.382583. As for CSS_J034112.5+035336, it was listed as an EW-type binary in VSX with a period of 0.285554 days. However, the LAMOST data showed that it is a special target because its temperature is very higher when compared with the short period. Our new photometric observations reveal it is a pulsating star rather than an EW-type binary. These results indicate that they the LAMOST data are very useful to understand their physical properties and evolutionary states.

An analysis of the times of minimum light for the long-period Algol-type eclipsing binary RX Gem is presented based on a new linear ephemeris. The curve shows a cyclic oscillation with a period O Ϫ C of 55.7 yr and a semiamplitude of 0.0645 day. Assuming the change to be due to the presence of a "third body" revolving around the RX Gem system, the parameters of the third body's orbit are derived. Since the third-body assumption is in good agreement with the spectroscopic data from several authors and with published photometric solutions (Gaposchkin, Hall, & Walter; Giuricin et al.), RX Gem is likely to be a triple system. In this case, the third body is an A-type star in a circular orbit, which is nearly coplanar to the orbit of the eclipsing pair. However, the recent light-curve analysis by Olson & Etzel does not show any third light, so the third star ( ) M 1 2.41 M 3 , may be an unseen neutron star or black hole. Additional eclipse timings over the next decade will be important to verify the presence of the third body.

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